diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index abc0b53191e..c624fd6fb60 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -126,7 +126,7 @@ class UsersController < ApplicationController
   def check_username
     if !params[:username].present?
       params.require(:username) if !params[:email].present?
-      return render(json: success_json) unless SiteSetting.call_discourse_hub?
+      return render(json: success_json)
     end
     username = params[:username]
 
@@ -138,8 +138,6 @@ class UsersController < ApplicationController
     checker = UsernameCheckerService.new
     email = params[:email] || target_user.try(:email)
     render json: checker.check_username(username, email)
-  rescue RestClient::Forbidden
-    render json: {errors: [I18n.t("discourse_hub.access_token_problem")]}
   end
 
   def user_from_params_or_current_user
@@ -195,8 +193,6 @@ class UsersController < ApplicationController
       success: false,
       message: I18n.t("login.something_already_taken")
     }
-  rescue DiscourseHub::UsernameUnavailable => e
-    render json: e.response_message
   rescue RestClient::Forbidden
     render json: { errors: [I18n.t("discourse_hub.access_token_problem")] }
   end
diff --git a/app/models/admin_dashboard_data.rb b/app/models/admin_dashboard_data.rb
index e6dbd86966f..e182de003ba 100644
--- a/app/models/admin_dashboard_data.rb
+++ b/app/models/admin_dashboard_data.rb
@@ -43,8 +43,7 @@ class AdminDashboardData
       site_description_check,
       access_password_removal,
       site_contact_username_check,
-      notification_email_check,
-      enforce_global_nicknames_check
+      notification_email_check
     ].compact
   end
 
@@ -186,10 +185,6 @@ class AdminDashboardData
     I18n.t('dashboard.ruby_version_warning') if RUBY_VERSION == '2.0.0' and RUBY_PATCHLEVEL < 247
   end
 
-  def enforce_global_nicknames_check
-    I18n.t('dashboard.enforce_global_nicknames_warning') if SiteSetting.enforce_global_nicknames and !SiteSetting.discourse_org_access_key.present?
-  end
-
   # TODO: generalize this method of putting i18n keys with expiry in redis
   #       that should be reported on the admin dashboard:
   def access_password_removal
diff --git a/app/models/invite_redeemer.rb b/app/models/invite_redeemer.rb
index c7eb58711c9..a722c80e94d 100644
--- a/app/models/invite_redeemer.rb
+++ b/app/models/invite_redeemer.rb
@@ -29,16 +29,9 @@ InviteRedeemer = Struct.new(:invite, :username, :name) do
     end
     available_name = name || available_username
 
-    DiscourseHub.username_operation do
-      match, available, suggestion = DiscourseHub.username_match?(available_username, invite.email)
-      available_username = suggestion unless match || available
-    end
-
     user = User.new(email: invite.email, username: available_username, name: available_name, active: true, trust_level: SiteSetting.default_invitee_trust_level)
     user.save!
 
-    DiscourseHub.username_operation { DiscourseHub.register_username(username, invite.email) }
-
     user
   end
 
diff --git a/app/models/site_setting.rb b/app/models/site_setting.rb
index 98dfe84f73c..108230589fb 100644
--- a/app/models/site_setting.rb
+++ b/app/models/site_setting.rb
@@ -29,10 +29,6 @@ class SiteSetting < ActiveRecord::Base
     LocaleSiteSetting.values.map{ |e| e[:value] }.join('|')
   end
 
-  def self.call_discourse_hub?
-    self.enforce_global_nicknames? && self.discourse_org_access_key.present?
-  end
-
   def self.topic_title_length
     min_topic_title_length..max_topic_title_length
   end
diff --git a/app/models/user.rb b/app/models/user.rb
index 856354fe85a..8df23499ff0 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -106,14 +106,8 @@ class User < ActiveRecord::Base
     LAST_VISIT = -2
   end
 
-  GLOBAL_USERNAME_LENGTH_RANGE = 3..15
-
   def self.username_length
-    if SiteSetting.enforce_global_nicknames
-      GLOBAL_USERNAME_LENGTH_RANGE
-    else
-      SiteSetting.min_username_length.to_i..SiteSetting.max_username_length.to_i
-    end
+    SiteSetting.min_username_length.to_i..SiteSetting.max_username_length.to_i
   end
 
   def custom_groups
@@ -176,11 +170,6 @@ class User < ActiveRecord::Base
   def change_username(new_username)
     current_username = self.username
     self.username = new_username
-
-    if current_username.downcase != new_username.downcase && valid?
-      DiscourseHub.username_operation { DiscourseHub.change_username(current_username, new_username) }
-    end
-
     save
   end
 
diff --git a/app/services/user_activator.rb b/app/services/user_activator.rb
index 7d20c6d7544..d96c8ca981c 100644
--- a/app/services/user_activator.rb
+++ b/app/services/user_activator.rb
@@ -6,13 +6,10 @@ class UserActivator
     @session = session
     @cookies = cookies
     @request = request
-    @settings = SiteSetting
-    @hub = DiscourseHub
     @message = nil
   end
 
   def start
-    register_username
   end
 
   def finish
@@ -26,7 +23,7 @@ class UserActivator
   end
 
   def factory
-    if @settings.must_approve_users?
+    if SiteSetting.must_approve_users?
       ApprovalActivator
     elsif !user.active?
       EmailActivator
@@ -35,11 +32,6 @@ class UserActivator
     end
   end
 
-  def register_username
-    if user.valid? && @settings.call_discourse_hub?
-      @hub.register_username(user.username, user.email)
-    end
-  end
 end
 
 class ApprovalActivator < UserActivator
diff --git a/app/services/user_destroyer.rb b/app/services/user_destroyer.rb
index f2d5505cedd..55f88a00458 100644
--- a/app/services/user_destroyer.rb
+++ b/app/services/user_destroyer.rb
@@ -61,7 +61,6 @@ class UserDestroyer
           end
 
           StaffActionLogger.new(@actor == user ? Discourse.system_user : @actor).log_user_deletion(user, opts.slice(:context))
-          DiscourseHub.unregister_username(user.username) if SiteSetting.call_discourse_hub?
           MessageBus.publish "/file-change", ["refresh"], user_ids: [user.id]
         end
       end
diff --git a/app/services/username_checker_service.rb b/app/services/username_checker_service.rb
index 83f9562db53..caeea977aef 100644
--- a/app/services/username_checker_service.rb
+++ b/app/services/username_checker_service.rb
@@ -5,54 +5,13 @@ class UsernameCheckerService
       validator = UsernameValidator.new(username)
       if !validator.valid_format?
         {errors: validator.errors}
-      elsif !SiteSetting.call_discourse_hub?
-        check_username_locally(username)
       else
-        check_username_with_hub_server(username, email)
-      end
-    elsif email and SiteSetting.call_discourse_hub?
-      username_from_hub = DiscourseHub.username_for_email(email)
-      if username_from_hub && User.username_available?(username_from_hub)
-        {suggestion: username_from_hub}
-      else
-        {suggestion: nil}
+        check_username_availability(username)
       end
     end
   end
 
-  # Contact the Discourse Hub server
-  def check_username_with_hub_server(username, email)
-    available_locally             = User.username_available?(username)
-    info                          = available_globally_and_suggestion_from_hub(username, email)
-    available_globally            = info[:available_globally]
-    suggestion_from_discourse_hub = info[:suggestion_from_discourse_hub]
-    global_match                  = info[:global_match]
-    if available_globally && available_locally
-      { available: true, global_match: (global_match ? true : false) }
-    elsif available_locally && !available_globally
-      if email.present?
-        # Nickname and email do not match what's registered on the discourse hub.
-        { available: false, global_match: false, suggestion: suggestion_from_discourse_hub }
-      else
-        # The username is available locally, but is registered on the discourse hub.
-        # We need an email to see if the username belongs to this person.
-        # Don't give a suggestion until we get the email and try to match it with on the discourse hub.
-        { available: false }
-      end
-    elsif available_globally && !available_locally
-      # Already registered on this site with the matching username and email address. Why are you signing up again?
-      { available: false, suggestion: UserNameSuggester.suggest(username) }
-    else
-      # Not available anywhere.
-      render_unavailable_with_suggestion(suggestion_from_discourse_hub)
-    end
-  end
-
-  def render_unavailable_with_suggestion(suggestion)
-    { available: false, suggestion: suggestion }
-  end
-
-  def check_username_locally(username)
+  def check_username_availability(username)
     if User.username_available?(username)
       { available: true }
     else
@@ -60,18 +19,4 @@ class UsernameCheckerService
     end
   end
 
-  def available_globally_and_suggestion_from_hub(username, email)
-    if email.present?
-      global_match, available, suggestion =
-        DiscourseHub.username_match?(username, email)
-      { available_globally:            available || global_match,
-        suggestion_from_discourse_hub: suggestion,
-        global_match:                  global_match }
-    else
-      args = DiscourseHub.username_available?(username)
-      { available_globally:            args[0],
-        suggestion_from_discourse_hub: args[1],
-        global_match:                  false }
-    end
-  end
 end
diff --git a/config/application.rb b/config/application.rb
index 1922a73d5a5..b7b75d5a377 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -93,8 +93,7 @@ module Discourse
         :s3_secret_access_key,
         :twitter_consumer_secret,
         :facebook_app_secret,
-        :github_client_secret,
-        :discourse_org_access_key,
+        :github_client_secret
     ]
 
     # Enable the asset pipeline
diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index f9472290fa4..131a6466c2c 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -574,7 +574,6 @@ en:
     access_password_removal: "Your site was using the access_password setting, which has been removed. The login_required and must_approve_users settings have been enabled, which should be used instead. You can change them in the <a href='/admin/site_settings'>Site Settings</a>. Be sure to <a href='/admin/users/list/pending'>approve users in the Pending Users list</a>. (This message will go away after 2 days.)"
     site_contact_username_warning: "The site_contact_username setting is blank. Please update it in the <a href='/admin/site_settings'>Site Settings</a>. Set it to the username of an admin user who should be the sender of system messages."
     notification_email_warning: "The notification_email setting is blank. Please update it in the <a href='/admin/site_settings'>Site Settings</a>."
-    enforce_global_nicknames_warning: "The enforce_global_nicknames setting is checked, but the discourse_org_access_key is blank. A Discourse.org access key is required to use the enforce_global_nicknames setting. Please update your <a href='/admin/site_settings'>Site Settings</a>."
 
   content_types:
     education_new_reply:
@@ -640,8 +639,6 @@ en:
     uncategorized_description: "The description of the uncategorized category. Leave blank for no description."
     allow_duplicate_topic_titles: "Allow topics with identical, duplicate titles."
     unique_posts_mins: "How many minutes before a user can make a post with the same content again"
-    enforce_global_nicknames: "Enforce global username uniqueness (WARNING: only change this during initial setup)"
-    discourse_org_access_key: "The access key used to access the Discourse Hub username registry at discourse.org"
     educate_until_posts: "When the user starts typing their first (n) new posts, show the pop-up new user education panel in the composer."
     title: "Brief title of this site, used in the title tag."
     site_description: "Describe this site in one sentence, used in the meta description tag."
@@ -1606,9 +1603,6 @@ en:
 
         If the above link is not clickable, try copying and pasting it into the address bar of your web browser.
 
-  discourse_hub:
-    access_token_problem: "Tell an admin: Please update the site settings to include the correct discourse_org_access_key."
-
   page_not_found:
     title: "The page you requested doesn't exist or is private."
     popular_topics: "Popular"
diff --git a/config/site_settings.yml b/config/site_settings.yml
index 255baac5ebd..f9f012f8b96 100644
--- a/config/site_settings.yml
+++ b/config/site_settings.yml
@@ -246,8 +246,12 @@ users:
     default: 8
     min: 1
   block_common_passwords: true
-  enforce_global_nicknames: false
-  discourse_org_access_key: ''
+  enforce_global_nicknames:
+    default: false
+    hidden: true
+  discourse_org_access_key:
+    default: ''
+    hidden: true
   username_change_period: 3
   auto_track_topics_after: 240000
   email_editable: true
diff --git a/lib/discourse_hub.rb b/lib/discourse_hub.rb
index 9087f782c9c..e36768620d2 100644
--- a/lib/discourse_hub.rb
+++ b/lib/discourse_hub.rb
@@ -3,63 +3,6 @@ require_dependency 'version'
 
 module DiscourseHub
 
-  class UsernameUnavailable < RuntimeError
-    def initialize(username)
-      @username = username
-    end
-
-    def response_message
-      {
-        success: false,
-        message: I18n.t(
-          "login.errors",
-          errors:I18n.t(
-            "login.not_available", suggestion: UserNameSuggester.suggest(@username)
-          )
-        )
-      }
-    end
-
-  end
-
-  def self.username_available?(username)
-    json = get('/users/username_available', {username: username})
-    [json['available'], json['suggestion']]
-  end
-
-  def self.username_match?(username, email)
-    json = get('/users/username_match', {username: username, email: email})
-    [json['match'], json['available'] || false, json['suggestion']]
-  end
-
-  def self.username_for_email(email)
-    json = get('/users/username_match', {email: email})
-    json['suggestion']
-  end
-
-  def self.register_username(username, email)
-    json = post('/users', {username: username, email: email})
-    if json.has_key?('success')
-      true
-    else
-      raise UsernameUnavailable.new(username)  # TODO: report ALL the errors
-    end
-  end
-
-  def self.unregister_username(username)
-    json = delete('/memberships/' + username)
-    json.has_key?('success')
-  end
-
-  def self.change_username(current_username, new_username)
-    json = put("/users/#{current_username}/username", {username: new_username})
-    if json.has_key?('success')
-      true
-    else
-      raise UsernameUnavailable.new(new_username)  # TODO: report ALL the errors
-    end
-  end
-
   def self.version_check_payload
     {
       installed_version: Discourse::VERSION::STRING,
@@ -103,11 +46,11 @@ module DiscourseHub
   end
 
   def self.singular_action(action, rel_url, params={})
-    JSON.parse RestClient.send(action, "#{hub_base_url}#{rel_url}", {params: {access_token: access_token}.merge(params), accept: accepts } )
+    JSON.parse RestClient.send(action, "#{hub_base_url}#{rel_url}", {params: params, accept: accepts } )
   end
 
   def self.collection_action(action, rel_url, params={})
-    JSON.parse RestClient.send(action, "#{hub_base_url}#{rel_url}", {access_token: access_token}.merge(params), content_type: :json, accept: accepts )
+    JSON.parse RestClient.send(action, "#{hub_base_url}#{rel_url}", params, content_type: :json, accept: accepts )
   end
 
   def self.hub_base_url
@@ -118,23 +61,8 @@ module DiscourseHub
     end
   end
 
-  def self.access_token
-    SiteSetting.discourse_org_access_key
-  end
-
   def self.accepts
     [:json, 'application/vnd.discoursehub.v1']
   end
 
-  def self.username_operation
-    if SiteSetting.call_discourse_hub?
-      begin
-        yield
-      rescue DiscourseHub::UsernameUnavailable
-        false
-      rescue => e
-        Rails.logger.error e.message + "\n" + e.backtrace.join("\n")
-      end
-    end
-  end
 end
diff --git a/spec/components/discourse_hub_spec.rb b/spec/components/discourse_hub_spec.rb
index ead432b8b84..ea579d0e839 100644
--- a/spec/components/discourse_hub_spec.rb
+++ b/spec/components/discourse_hub_spec.rb
@@ -2,71 +2,6 @@ require 'spec_helper'
 require_dependency 'discourse_hub'
 
 describe DiscourseHub do
-  describe '#username_available?' do
-    it 'should return true when username is available and no suggestion' do
-      RestClient.stubs(:get).returns( {success: 'OK', available: true}.to_json )
-      DiscourseHub.username_available?('MacGyver').should == [true, nil]
-    end
-
-    it 'should return false and a suggestion when username is not available' do
-      RestClient.stubs(:get).returns( {success: 'OK', available: false, suggestion: 'MacGyver1'}.to_json )
-      available, suggestion = DiscourseHub.username_available?('MacGyver')
-      available.should be_false
-      suggestion.should_not be_nil
-    end
-
-    # How to handle connect errors? timeout? 401? 403? 429?
-  end
-
-  describe '#username_match?' do
-    it 'should return true when it is a match and no suggestion' do
-      RestClient.stubs(:get).returns( {success: 'OK', match: true, available: false}.to_json )
-      DiscourseHub.username_match?('MacGyver', 'macg@example.com').should == [true, false, nil]
-    end
-
-    it 'should return false and a suggestion when it is not a match and the username is not available' do
-      RestClient.stubs(:get).returns( {success: 'OK', match: false, available: false, suggestion: 'MacGyver1'}.to_json )
-      match, available, suggestion = DiscourseHub.username_match?('MacGyver', 'macg@example.com')
-      match.should be_false
-      available.should be_false
-      suggestion.should_not be_nil
-    end
-
-    it 'should return false and no suggestion when it is not a match and the username is available' do
-      RestClient.stubs(:get).returns( {success: 'OK', match: false, available: true}.to_json )
-      match, available, suggestion = DiscourseHub.username_match?('MacGyver', 'macg@example.com')
-      match.should be_false
-      available.should be_true
-      suggestion.should be_nil
-    end
-  end
-
-  describe '#register_username' do
-    it 'should return true when registration succeeds' do
-      RestClient.stubs(:post).returns( {success: 'OK'}.to_json )
-      DiscourseHub.register_username('MacGyver', 'macg@example.com').should be_true
-    end
-
-    it 'should return raise an exception when registration fails' do
-      RestClient.stubs(:post).returns( {failed: -200}.to_json )
-      expect {
-        DiscourseHub.register_username('MacGyver', 'macg@example.com')
-      }.to raise_error(DiscourseHub::UsernameUnavailable)
-    end
-  end
-
-  describe '#unregister_username' do
-    it 'should return true when unregister succeeds' do
-      RestClient.stubs(:delete).returns( {success: 'OK'}.to_json )
-      DiscourseHub.unregister_username('byebye').should be_true
-    end
-
-    it 'should return false when unregister fails' do
-      RestClient.stubs(:delete).returns( {failed: -20}.to_json )
-      DiscourseHub.unregister_username('byebye').should be_false
-    end
-  end
-
   describe '#discourse_version_check' do
     it 'should return just return the json that the hub returns' do
       hub_response = {'success' => 'OK', 'latest_version' => '0.8.1', 'critical_updates' => false}
@@ -74,33 +9,4 @@ describe DiscourseHub do
       DiscourseHub.discourse_version_check.should == hub_response
     end
   end
-
-  describe '#change_username' do
-    it 'should return true when username is changed successfully' do
-      RestClient.stubs(:put).returns( {success: 'OK'}.to_json )
-      DiscourseHub.change_username('MacGyver', 'MacG').should be_true
-    end
-
-    it 'should return raise UsernameUnavailable when username is not available' do
-      RestClient.stubs(:put).returns( {failed: -200}.to_json )
-      expect {
-        DiscourseHub.change_username('MacGyver', 'MacG')
-      }.to raise_error(DiscourseHub::UsernameUnavailable)
-    end
-
-
-    # it 'should return raise UsernameUnavailable when username does not belong to this forum' do
-    #   RestClient.stubs(:put).returns( {failed: -13}.to_json )
-    #   expect {
-    #      DiscourseHub.change_username('MacGyver', 'MacG')
-    #   }.to raise_error(DiscourseHub::ActionForbidden)
-    # end
-
-    # it 'should return raise UsernameUnavailable when username does not belong to this forum' do
-    #   RestClient.stubs(:put).returns( {failed: -13}.to_json )
-    #   expect {
-    #     DiscourseHub.change_username('MacGyver', 'MacG')
-    #   }.to raise_error(DiscourseHub::ActionForbidden)
-    # end
-  end
 end
diff --git a/spec/controllers/users_controller_spec.rb b/spec/controllers/users_controller_spec.rb
index 7c618a2ef41..8f127939df9 100644
--- a/spec/controllers/users_controller_spec.rb
+++ b/spec/controllers/users_controller_spec.rb
@@ -288,7 +288,6 @@ describe UsersController do
       SiteSetting.stubs(:allow_new_registrations).returns(true)
       @user = Fabricate.build(:user)
       @user.password = "strongpassword"
-      DiscourseHub.stubs(:register_username).returns([true, nil])
     end
 
     def post_user
@@ -494,25 +493,9 @@ describe UsersController do
       include_examples 'failed signup'
     end
 
-    context 'when username is unavailable in DiscourseHub' do
-      before do
-        SiteSetting.stubs(:call_discourse_hub?).returns(true)
-        DiscourseHub.stubs(:register_username).raises(DiscourseHub::UsernameUnavailable.new(@user.name))
-      end
-      let(:create_params) {{
-        name: @user.name,
-        username: @user.username,
-        password: 'strongpassword',
-        email: @user.email
-      }}
-
-      include_examples 'failed signup'
-    end
-
     context 'when an Exception is raised' do
 
       [ ActiveRecord::StatementInvalid,
-        DiscourseHub::UsernameUnavailable,
         RestClient::Forbidden ].each do |exception|
         before { User.any_instance.stubs(:save).raises(exception) }
 
@@ -561,15 +544,11 @@ describe UsersController do
   end
 
   context '.check_username' do
-    before do
-      DiscourseHub.stubs(:username_available?).returns([true, nil])
-    end
-
     it 'raises an error without any parameters' do
       lambda { xhr :get, :check_username }.should raise_error(ActionController::ParameterMissing)
     end
 
-    shared_examples 'when username is unavailable locally' do
+    shared_examples 'when username is unavailable' do
       it 'should return success' do
         response.should be_success
       end
@@ -583,7 +562,7 @@ describe UsersController do
       end
     end
 
-    shared_examples 'when username is available everywhere' do
+    shared_examples 'when username is available' do
       it 'should return success' do
         response.should be_success
       end
@@ -593,211 +572,59 @@ describe UsersController do
       end
     end
 
-    context 'when call_discourse_hub is disabled' do
-      before do
-        SiteSetting.stubs(:call_discourse_hub?).returns(false)
-        DiscourseHub.expects(:username_available?).never
-        DiscourseHub.expects(:username_match?).never
-      end
+    it 'returns nothing when given an email param but no username' do
+      xhr :get, :check_username, email: 'dood@example.com'
+      response.should be_success
+    end
 
-      it 'returns nothing when given an email param but no username' do
-        xhr :get, :check_username, email: 'dood@example.com'
+    context 'username is available' do
+      before do
+        xhr :get, :check_username, username: 'BruceWayne'
+      end
+      include_examples 'when username is available'
+    end
+
+    context 'username is unavailable' do
+      let!(:user) { Fabricate(:user) }
+      before do
+        xhr :get, :check_username, username: user.username
+      end
+      include_examples 'when username is unavailable'
+    end
+
+    shared_examples 'checking an invalid username' do
+      it 'should return success' do
         response.should be_success
       end
 
-      context 'username is available' do
-        before do
-          xhr :get, :check_username, username: 'BruceWayne'
-        end
-        include_examples 'when username is available everywhere'
-      end
-
-      context 'username is unavailable' do
-        let!(:user) { Fabricate(:user) }
-        before do
-          xhr :get, :check_username, username: user.username
-        end
-        include_examples 'when username is unavailable locally'
-      end
-
-      shared_examples 'checking an invalid username' do
-        it 'should return success' do
-          response.should be_success
-        end
-
-        it 'should not return an available key' do
-          ::JSON.parse(response.body)['available'].should be_nil
-        end
-
-        it 'should return an error message' do
-          ::JSON.parse(response.body)['errors'].should_not be_empty
-        end
-      end
-
-      context 'has invalid characters' do
-        before do
-          xhr :get, :check_username, username: 'bad username'
-        end
-        include_examples 'checking an invalid username'
-
-        it 'should return the invalid characters message' do
-          ::JSON.parse(response.body)['errors'].should include(I18n.t(:'user.username.characters'))
-        end
-      end
-
-      context 'is too long' do
-        before do
-          xhr :get, :check_username, username: generate_username(User.username_length.last + 1)
-        end
-        include_examples 'checking an invalid username'
-
-        it 'should return the "too long" message' do
-          ::JSON.parse(response.body)['errors'].should include(I18n.t(:'user.username.long', max: User.username_length.end))
-        end
-      end
-    end
-
-    context 'when call_discourse_hub is enabled' do
-      before do
-        SiteSetting.stubs(:call_discourse_hub?).returns(true)
-      end
-
-      context 'available locally and globally' do
-        before do
-          DiscourseHub.stubs(:username_available?).returns([true, nil])
-          DiscourseHub.stubs(:username_match?).returns([false, true, nil])  # match = false, available = true, suggestion = nil
-        end
-
-        shared_examples 'check_username when username is available everywhere' do
-          it 'should return success' do
-            response.should be_success
-          end
-
-          it 'should return available in the JSON' do
-            ::JSON.parse(response.body)['available'].should be_true
-          end
-
-          it 'should return global_match false in the JSON' do
-            ::JSON.parse(response.body)['global_match'].should be_false
-          end
-        end
-
-        context 'and email is not given' do
-          before do
-            xhr :get, :check_username, username: 'BruceWayne'
-          end
-          include_examples 'check_username when username is available everywhere'
-        end
-
-        context 'both username and email is given' do
-          before do
-            xhr :get, :check_username, username: 'BruceWayne', email: 'brucie@gmail.com'
-          end
-          include_examples 'check_username when username is available everywhere'
-        end
-
-        context 'only email is given' do
-          it "should check for a matching username" do
-            UsernameCheckerService.any_instance.expects(:check_username).with(nil, 'brucie@gmail.com').returns({json: 'blah'})
-            xhr :get, :check_username, email: 'brucie@gmail.com'
-            response.should be_success
-          end
-        end
-      end
-
-      shared_examples 'when email is needed to check username match' do
-        it 'should return success' do
-          response.should be_success
-        end
-
-        it 'should return available as false in the JSON' do
-          ::JSON.parse(response.body)['available'].should be_false
-        end
-
-        it 'should not return a suggested username' do
-          ::JSON.parse(response.body)['suggestion'].should_not be_present
-        end
-      end
-
-      context 'available locally but not globally' do
-        before do
-          DiscourseHub.stubs(:username_available?).returns([false, 'suggestion'])
-        end
-
-        context 'email param is not given' do
-          before do
-            xhr :get, :check_username, username: 'BruceWayne'
-          end
-          include_examples 'when email is needed to check username match'
-        end
-
-        context 'email param is an empty string' do
-          before do
-            xhr :get, :check_username, username: 'BruceWayne', email: ''
-          end
-          include_examples 'when email is needed to check username match'
-        end
-
-        context 'email matches global username' do
-          before do
-            DiscourseHub.stubs(:username_match?).returns([true, false, nil])
-            xhr :get, :check_username, username: 'BruceWayne', email: 'brucie@example.com'
-          end
-          include_examples 'when username is available everywhere'
-
-          it 'should indicate a global match' do
-            ::JSON.parse(response.body)['global_match'].should be_true
-          end
-        end
-
-        context 'email does not match global username' do
-          before do
-            DiscourseHub.stubs(:username_match?).returns([false, false, 'suggestion'])
-            xhr :get, :check_username, username: 'BruceWayne', email: 'brucie@example.com'
-          end
-          include_examples 'when username is unavailable locally'
-
-          it 'should not indicate a global match' do
-            ::JSON.parse(response.body)['global_match'].should be_false
-          end
-        end
-      end
-
-      context 'unavailable locally and globally' do
-        let!(:user) { Fabricate(:user) }
-
-        before do
-          DiscourseHub.stubs(:username_available?).returns([false, 'suggestion'])
-          xhr :get, :check_username, username: user.username
-        end
-
-        include_examples 'when username is unavailable locally'
-      end
-
-      context 'unavailable locally and available globally' do
-        let!(:user) { Fabricate(:user) }
-
-        before do
-          DiscourseHub.stubs(:username_available?).returns([true, nil])
-          xhr :get, :check_username, username: user.username
-        end
-
-        include_examples 'when username is unavailable locally'
-      end
-    end
-
-    context 'when discourse_org_access_key is wrong' do
-      before do
-        SiteSetting.stubs(:call_discourse_hub?).returns(true)
-        DiscourseHub.stubs(:username_available?).raises(RestClient::Forbidden)
-        DiscourseHub.stubs(:username_match?).raises(RestClient::Forbidden)
+      it 'should not return an available key' do
+        ::JSON.parse(response.body)['available'].should be_nil
       end
 
       it 'should return an error message' do
-        xhr :get, :check_username, username: 'horsie'
-        json = JSON.parse(response.body)
-        json['errors'].should_not be_nil
-        json['errors'][0].should_not be_nil
+        ::JSON.parse(response.body)['errors'].should_not be_empty
+      end
+    end
+
+    context 'has invalid characters' do
+      before do
+        xhr :get, :check_username, username: 'bad username'
+      end
+      include_examples 'checking an invalid username'
+
+      it 'should return the invalid characters message' do
+        ::JSON.parse(response.body)['errors'].should include(I18n.t(:'user.username.characters'))
+      end
+    end
+
+    context 'is too long' do
+      before do
+        xhr :get, :check_username, username: generate_username(User.username_length.last + 1)
+      end
+      include_examples 'checking an invalid username'
+
+      it 'should return the "too long" message' do
+        ::JSON.parse(response.body)['errors'].should include(I18n.t(:'user.username.long', max: User.username_length.end))
       end
     end
 
@@ -808,7 +635,7 @@ describe UsersController do
           log_in_user(user)
           xhr :get, :check_username, username: 'HanSolo'
         end
-        include_examples 'when username is available everywhere'
+        include_examples 'when username is available'
       end
 
       context "it's someone else's username" do
@@ -817,7 +644,7 @@ describe UsersController do
           log_in
           xhr :get, :check_username, username: 'HanSolo'
         end
-        include_examples 'when username is unavailable locally'
+        include_examples 'when username is unavailable'
       end
 
       context "an admin changing it for someone else" do
@@ -826,7 +653,7 @@ describe UsersController do
           log_in_user(Fabricate(:admin))
           xhr :get, :check_username, username: 'HanSolo', for_user_id: user.id
         end
-        include_examples 'when username is available everywhere'
+        include_examples 'when username is available'
       end
     end
   end
diff --git a/spec/models/admin_dashboard_data_spec.rb b/spec/models/admin_dashboard_data_spec.rb
index b8da3fc38ff..414c296c261 100644
--- a/spec/models/admin_dashboard_data_spec.rb
+++ b/spec/models/admin_dashboard_data_spec.rb
@@ -244,26 +244,4 @@ describe AdminDashboardData do
     end
   end
 
-  describe "enforce_global_nicknames_check" do
-    subject { described_class.new.enforce_global_nicknames_check }
-
-    it 'returns nil when enforce_global_nicknames and discourse_org_access_key are set' do
-      SiteSetting.stubs(:enforce_global_nicknames).returns(true)
-      SiteSetting.stubs(:discourse_org_access_key).returns('123')
-      subject.should be_nil
-    end
-
-    it 'returns a string when enforce_global_nicknames is true but discourse_org_access_key is not' do
-      SiteSetting.stubs(:enforce_global_nicknames).returns(true)
-      SiteSetting.stubs(:discourse_org_access_key).returns('')
-      subject.should_not be_nil
-    end
-
-    it 'returns nil when enforce_global_nicknames is false and discourse_org_access_key is set' do
-      SiteSetting.stubs(:enforce_global_nicknames).returns(false)
-      SiteSetting.stubs(:discourse_org_access_key).returns('123')
-      subject.should be_nil
-    end
-  end
-
 end
diff --git a/spec/models/site_setting_spec.rb b/spec/models/site_setting_spec.rb
index e95ca790b51..778cc3536b9 100644
--- a/spec/models/site_setting_spec.rb
+++ b/spec/models/site_setting_spec.rb
@@ -4,32 +4,6 @@ require_dependency 'site_setting_extension'
 
 describe SiteSetting do
 
-  describe 'call_discourse_hub?' do
-    it 'should be true when enforce_global_nicknames is true and discourse_org_access_key is set' do
-      SiteSetting.stubs(:enforce_global_nicknames).returns(true)
-      SiteSetting.stubs(:discourse_org_access_key).returns('asdfasfsafd')
-      SiteSetting.call_discourse_hub?.should == true
-    end
-
-    it 'should be false when enforce_global_nicknames is false and discourse_org_access_key is set' do
-      SiteSetting.stubs(:enforce_global_nicknames).returns(false)
-      SiteSetting.stubs(:discourse_org_access_key).returns('asdfasfsafd')
-      SiteSetting.call_discourse_hub?.should == false
-    end
-
-    it 'should be false when enforce_global_nicknames is true and discourse_org_access_key is not set' do
-      SiteSetting.stubs(:enforce_global_nicknames).returns(true)
-      SiteSetting.stubs(:discourse_org_access_key).returns('')
-      SiteSetting.call_discourse_hub?.should == false
-    end
-
-    it 'should be false when enforce_global_nicknames is false and discourse_org_access_key is not set' do
-      SiteSetting.stubs(:enforce_global_nicknames).returns(false)
-      SiteSetting.stubs(:discourse_org_access_key).returns('')
-      SiteSetting.call_discourse_hub?.should == false
-    end
-  end
-
   describe "normalized_embeddable_host" do
     it 'returns the `embeddable_host` value' do
       SiteSetting.stubs(:embeddable_host).returns("eviltrout.com")
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index b39ce620ca6..fe55d6415db 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -143,7 +143,7 @@ describe User do
 
     describe 'allow custom minimum username length from site settings' do
       before do
-        @custom_min = User::GLOBAL_USERNAME_LENGTH_RANGE.begin - 1
+        @custom_min = 2
         SiteSetting.min_username_length = @custom_min
       end
 
@@ -161,11 +161,6 @@ describe User do
         result = user.change_username('a' * (User.username_length.end + 1))
         result.should be_false
       end
-
-      it 'should use default length for validation if enforce_global_nicknames is true' do
-        SiteSetting.enforce_global_nicknames = true
-        User::username_length.should == User::GLOBAL_USERNAME_LENGTH_RANGE
-      end
     end
   end
 
diff --git a/spec/services/user_destroyer_spec.rb b/spec/services/user_destroyer_spec.rb
index 4e9ebf613cb..1d1d10db452 100644
--- a/spec/services/user_destroyer_spec.rb
+++ b/spec/services/user_destroyer_spec.rb
@@ -50,18 +50,6 @@ describe UserDestroyer do
         StaffActionLogger.any_instance.expects(:log_user_deletion).with(@user, anything).once
         destroy
       end
-
-      it 'should unregister the nickname as the discourse hub if hub integration is enabled' do
-        SiteSetting.stubs(:call_discourse_hub?).returns(true)
-        DiscourseHub.expects(:unregister_username).with(@user.username)
-        destroy
-      end
-
-      it 'should not try to unregister the nickname as the discourse hub if hub integration is disabled' do
-        SiteSetting.stubs(:call_discourse_hub?).returns(false)
-        DiscourseHub.expects(:unregister_username).never
-        destroy
-      end
     end
 
     shared_examples "email block list" do
@@ -106,11 +94,6 @@ describe UserDestroyer do
           StaffActionLogger.any_instance.expects(:log_user_deletion).never
           destroy rescue nil
         end
-
-        it 'should not unregister the user at the discourse hub' do
-          DiscourseHub.expects(:unregister_username).never
-          destroy rescue nil
-        end
       end
 
       context "delete_posts is true" do
@@ -190,11 +173,6 @@ describe UserDestroyer do
           StaffActionLogger.any_instance.expects(:log_user_deletion).never
           destroy
         end
-
-        it 'should not unregister the user at the discourse hub' do
-          DiscourseHub.expects(:unregister_username).never
-          destroy rescue nil
-        end
       end
     end
 
diff --git a/spec/services/username_checker_service_spec.rb b/spec/services/username_checker_service_spec.rb
index 46c95701290..6c05448e483 100644
--- a/spec/services/username_checker_service_spec.rb
+++ b/spec/services/username_checker_service_spec.rb
@@ -31,105 +31,18 @@ describe UsernameCheckerService do
       end
     end
 
-    context 'Using Discourse Hub' do
-      before do
-        SiteSetting.stubs(:call_discourse_hub?).returns(true)
-      end
-
-      context 'username and email is given' do
-        it 'username is available locally but not globally' do
-          DiscourseHub.expects(:username_available?).never
-          DiscourseHub.expects(:username_match?).returns([false, false, 'porkchop'])
-          result = @service.check_username('vincent', @email)
-          expected = { available: false, global_match: false, suggestion: 'porkchop' }
-          expect(result).to eq(expected)
-        end
-
-        it 'username is available both locally and globally' do
-          DiscourseHub.expects(:username_available?).never
-          DiscourseHub.stubs(:username_match?).returns([true, true, nil])
-          result = @service.check_username('vincent', @email)
-          expected = { available: true, global_match: true }
-          expect(result).to eq(expected)
-        end
-
-        it 'username is available locally but not globally' do
-          DiscourseHub.stubs(:username_match?).returns([false, false, 'suggestion'])
-          result = @service.check_username('vincent', @email)
-          expected = { available: false, global_match: false, suggestion: 'suggestion' }
-          expect(result).to eq(expected)
-        end
-
-        it 'username is available globally but not locally' do
-          DiscourseHub.stubs(:username_match?).returns([false, true, nil])
-          User.stubs(:username_available?).returns(false)
-          UserNameSuggester.stubs(:suggest).returns('einar-j')
-          expected = { available: false, suggestion: 'einar-j' }
-          result = @service.check_username('vincent', @email)
-          expect(result).to eq(expected)
-        end
-
-        it 'username not available anywhere' do
-          DiscourseHub.stubs(:username_match?).returns([false, false, 'suggestion'])
-          expected = { available: false, suggestion: 'suggestion', global_match: false }
-          @nil_email = nil
-          result = @service.check_username('vincent', @email)
-          expect(result).to eq(expected)
-        end
-      end
-
-      shared_examples "only email is given" do
-        it "should call the correct api" do
-          DiscourseHub.expects(:username_available?).never
-          DiscourseHub.expects(:username_match?).never
-          DiscourseHub.stubs(:username_for_email).returns(nil)
-          result
-        end
-
-        it 'no match on email' do
-          DiscourseHub.stubs(:username_for_email).returns(nil)
-          result.should == {suggestion: nil}
-        end
-
-        it 'match found for email' do
-          DiscourseHub.stubs(:username_for_email).returns('vincent')
-          result.should == {suggestion: 'vincent'}
-        end
-
-        it 'match found for email, but username is taken' do
-          # This case can happen when you've already signed up on the site,
-          # or enforce_global_nicknames used to be disabled.
-          DiscourseHub.stubs(:username_for_email).returns('taken')
-          User.stubs(:username_available?).with('taken').returns(false)
-          result.should == {suggestion: nil}
-        end
-      end
-
-      context 'username is nil' do
-        subject(:result) { @service.check_username(nil, @email) }
-        include_examples "only email is given"
-      end
-
-      context 'username is empty string' do
-        subject(:result) { @service.check_username('', @email) }
-        include_examples "only email is given"
-      end
+    it 'username not available locally' do
+      User.stubs(:username_available?).returns(false)
+      UserNameSuggester.stubs(:suggest).returns('einar-j')
+      result = @service.check_username('vincent', @nil_email)
+      result[:available].should be_false
+      result[:suggestion].should eq('einar-j')
     end
 
-    context 'Discourse Hub disabled' do
-      it 'username not available locally' do
-        User.stubs(:username_available?).returns(false)
-        UserNameSuggester.stubs(:suggest).returns('einar-j')
-        result = @service.check_username('vincent', @nil_email)
-        result[:available].should be_false
-        result[:suggestion].should eq('einar-j')
-      end
-
-      it 'username available locally' do
-        User.stubs(:username_available?).returns(true)
-        result = @service.check_username('vincent', @nil_email)
-        result[:available].should be_true
-      end
+    it 'username available locally' do
+      User.stubs(:username_available?).returns(true)
+      result = @service.check_username('vincent', @nil_email)
+      result[:available].should be_true
     end
   end