diff --git a/Gemfile b/Gemfile
index 12fa31a0af6..3f5a46fb761 100644
--- a/Gemfile
+++ b/Gemfile
@@ -64,7 +64,7 @@ gem 'aws-sdk', require: false
 gem 'excon', require: false
 gem 'unf', require: false
 
-gem 'email_reply_trimmer', '0.0.6'
+gem 'email_reply_trimmer', '0.0.8'
 
 # note: for image_optim to correctly work you need to follow
 # https://github.com/toy/image_optim
diff --git a/Gemfile.lock b/Gemfile.lock
index 55d8c3d124b..a614c28a89b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -76,7 +76,7 @@ GEM
     docile (1.1.5)
     domain_name (0.5.25)
       unf (>= 0.0.5, < 1.0.0)
-    email_reply_trimmer (0.0.6)
+    email_reply_trimmer (0.0.8)
     ember-data-source (1.0.0.beta.16.1)
       ember-source (~> 1.8)
     ember-handlebars-template (0.1.5)
@@ -411,7 +411,7 @@ DEPENDENCIES
   byebug
   certified
   discourse-qunit-rails
-  email_reply_trimmer (= 0.0.6)
+  email_reply_trimmer (= 0.0.8)
   ember-rails
   ember-source (= 1.12.2)
   excon
diff --git a/app/assets/javascripts/discourse/controllers/preferences.js.es6 b/app/assets/javascripts/discourse/controllers/preferences.js.es6
index 1efdaff99be..5231e4fa430 100644
--- a/app/assets/javascripts/discourse/controllers/preferences.js.es6
+++ b/app/assets/javascripts/discourse/controllers/preferences.js.es6
@@ -62,6 +62,12 @@ export default Ember.Controller.extend(CanCheckEmails, {
     return this.siteSettings.available_locales.split('|').map(s => ({ name: s, value: s }));
   },
 
+  previousRepliesOptions: [
+    {name: I18n.t('user.email_previous_replies.always'), value: 0},
+    {name: I18n.t('user.email_previous_replies.unless_emailed'), value: 1},
+    {name: I18n.t('user.email_previous_replies.never'), value: 2}
+  ],
+
   digestFrequencies: [{ name: I18n.t('user.email_digests.daily'), value: 1 },
                       { name: I18n.t('user.email_digests.every_three_days'), value: 3 },
                       { name: I18n.t('user.email_digests.weekly'), value: 7 },
diff --git a/app/assets/javascripts/discourse/models/user.js.es6 b/app/assets/javascripts/discourse/models/user.js.es6
index c57574431e7..9eeb9f87b35 100644
--- a/app/assets/javascripts/discourse/models/user.js.es6
+++ b/app/assets/javascripts/discourse/models/user.js.es6
@@ -159,6 +159,7 @@ const User = RestModel.extend({
             'email_digests',
             'email_direct',
             'email_private_messages',
+            'email_previous_replies',
             'dynamic_favicon',
             'enable_quoting',
             'disable_jump_reply',
diff --git a/app/assets/javascripts/discourse/templates/user/preferences.hbs b/app/assets/javascripts/discourse/templates/user/preferences.hbs
index 06bab9cbf45..6e8c026a4d3 100644
--- a/app/assets/javascripts/discourse/templates/user/preferences.hbs
+++ b/app/assets/javascripts/discourse/templates/user/preferences.hbs
@@ -176,6 +176,10 @@
           </div>
         {{/if}}
       {{/if}}
+      <div class='controls controls-dropdown'>
+        <label>{{i18n 'user.email_previous_replies.title'}}</label>
+        {{combo-box valueAttribute="value" content=previousRepliesOptions value=model.user_option.email_previous_replies}}
+      </div>
       {{preference-checkbox labelKey="user.email_private_messages" checked=model.user_option.email_private_messages}}
       {{preference-checkbox labelKey="user.email_direct" checked=model.user_option.email_direct}}
       <span class="pref-mailing-list-mode">{{preference-checkbox labelKey="user.mailing_list_mode" checked=model.user_option.mailing_list_mode}}</span>
@@ -188,6 +192,9 @@
           {{i18n 'user.email.frequency_immediately'}}
         {{/if}}
       </div>
+
+
+
     </div>
 
     <div class="control-group notifications">
diff --git a/app/controllers/admin/groups_controller.rb b/app/controllers/admin/groups_controller.rb
index 62653c427e2..920cc34955d 100644
--- a/app/controllers/admin/groups_controller.rb
+++ b/app/controllers/admin/groups_controller.rb
@@ -28,28 +28,7 @@ class Admin::GroupsController < Admin::AdminController
     if group.present?
       users = (params[:users] || []).map {|u| u.downcase}
       user_ids = User.where("username_lower in (:users) OR email IN (:users)", users: users).pluck(:id)
-
-      if user_ids.present?
-        Group.exec_sql("INSERT INTO group_users
-                                    (group_id, user_id, created_at, updated_at)
-                       SELECT #{group.id},
-                              u.id,
-                              CURRENT_TIMESTAMP,
-                              CURRENT_TIMESTAMP
-                       FROM users AS u
-                       WHERE u.id IN (#{user_ids.join(', ')})
-                         AND NOT EXISTS(SELECT 1 FROM group_users AS gu
-                                        WHERE gu.user_id = u.id AND
-                                              gu.group_id = #{group.id})")
-
-        if group.primary_group?
-          User.where(id: user_ids).update_all(primary_group_id: group.id)
-        end
-
-        if group.title.present?
-          User.where(id: user_ids).update_all(title: group.title)
-        end
-      end
+      group.bulk_add(user_ids) if user_ids.present?
     end
 
     render json: success_json
diff --git a/app/jobs/scheduled/enqueue_digest_emails.rb b/app/jobs/scheduled/enqueue_digest_emails.rb
index ea74f98ed28..9c10f695730 100644
--- a/app/jobs/scheduled/enqueue_digest_emails.rb
+++ b/app/jobs/scheduled/enqueue_digest_emails.rb
@@ -19,8 +19,8 @@ module Jobs
                   .joins(:user_option)
                   .not_suspended
                   .where(user_options: {email_digests: true})
-                  .where("COALESCE(last_emailed_at, '2010-01-01') <= CURRENT_TIMESTAMP - ('1 DAY'::INTERVAL * digest_after_days)")
-                  .where("COALESCE(last_seen_at, '2010-01-01') <= CURRENT_TIMESTAMP - ('1 DAY'::INTERVAL * digest_after_days)")
+                  .where("COALESCE(last_emailed_at, '2010-01-01') <= CURRENT_TIMESTAMP - ('1 DAY'::INTERVAL * user_options.digest_after_days)")
+                  .where("COALESCE(last_seen_at, '2010-01-01') <= CURRENT_TIMESTAMP - ('1 DAY'::INTERVAL * user_options.digest_after_days)")
                   .where("COALESCE(last_seen_at, '2010-01-01') >= CURRENT_TIMESTAMP - ('1 DAY'::INTERVAL * #{SiteSetting.delete_digest_email_after_days})")
 
       # If the site requires approval, make sure the user is approved
diff --git a/app/mailers/user_notifications.rb b/app/mailers/user_notifications.rb
index 52db55f8ab6..e8def9ecce6 100644
--- a/app/mailers/user_notifications.rb
+++ b/app/mailers/user_notifications.rb
@@ -193,6 +193,11 @@ class UserNotifications < ActionMailer::Base
   end
 
   def self.get_context_posts(post, topic_user)
+    user_option = topic_user.try(:user).try(:user_option)
+    if user_option && (user_option.email_previous_replies == UserOption.previous_replies_type[:never])
+      return []
+    end
+
     allowed_post_types = [Post.types[:regular]]
     allowed_post_types << Post.types[:whisper] if topic_user.try(:user).try(:staff?)
 
@@ -204,7 +209,7 @@ class UserNotifications < ActionMailer::Base
                         .order('created_at desc')
                         .limit(SiteSetting.email_posts_context)
 
-    if topic_user && topic_user.last_emailed_post_number
+    if topic_user && topic_user.last_emailed_post_number && user_option.try(:email_previous_replies) == UserOption.previous_replies_type[:unless_emailed]
       context_posts = context_posts.where("post_number > ?", topic_user.last_emailed_post_number)
     end
 
diff --git a/app/models/group.rb b/app/models/group.rb
index a508335a77a..148b1e9e8d1 100644
--- a/app/models/group.rb
+++ b/app/models/group.rb
@@ -335,6 +335,31 @@ class Group < ActiveRecord::Base
     self.find_by(incoming_email: Email.downcase(email))
   end
 
+  def bulk_add(user_ids)
+    if user_ids.present?
+      Group.exec_sql("INSERT INTO group_users
+                                  (group_id, user_id, created_at, updated_at)
+                     SELECT #{self.id},
+                            u.id,
+                            CURRENT_TIMESTAMP,
+                            CURRENT_TIMESTAMP
+                     FROM users AS u
+                     WHERE u.id IN (#{user_ids.join(', ')})
+                       AND NOT EXISTS(SELECT 1 FROM group_users AS gu
+                                      WHERE gu.user_id = u.id AND
+                                            gu.group_id = #{self.id})")
+
+      if self.primary_group?
+        User.where(id: user_ids).update_all(primary_group_id: self.id)
+      end
+
+      if self.title.present?
+        User.where(id: user_ids).update_all(title: self.title)
+      end
+    end
+    true
+  end
+
   protected
 
     def name_format_validator
diff --git a/app/models/previous_replies_site_setting.rb b/app/models/previous_replies_site_setting.rb
new file mode 100644
index 00000000000..eac55ae5232
--- /dev/null
+++ b/app/models/previous_replies_site_setting.rb
@@ -0,0 +1,22 @@
+require_dependency 'enum_site_setting'
+
+class PreviousRepliesSiteSetting < EnumSiteSetting
+
+  def self.valid_value?(val)
+    val.to_i.to_s == val.to_s &&
+    values.any? { |v| v[:value] == val.to_i }
+  end
+
+  def self.values
+    @values ||= [
+      { name: 'user.email_previous_replies.always',  value:  0 },
+      { name: 'user.email_previous_replies.unless_emailed',   value:  1 },
+      { name: 'user.email_previous_replies.never', value:  2 },
+    ]
+  end
+
+  def self.translate_names?
+    true
+  end
+
+end
diff --git a/app/models/user_option.rb b/app/models/user_option.rb
index 46d7e673079..e6384f061b2 100644
--- a/app/models/user_option.rb
+++ b/app/models/user_option.rb
@@ -5,12 +5,17 @@ class UserOption < ActiveRecord::Base
 
   after_save :update_tracked_topics
 
+  def self.previous_replies_type
+    @previous_replies_type ||= Enum.new(always: 0, unless_emailed: 1, never: 2)
+  end
+
   def set_defaults
     self.email_always = SiteSetting.default_email_always
     self.mailing_list_mode = SiteSetting.default_email_mailing_list_mode
     self.email_direct = SiteSetting.default_email_direct
     self.automatically_unpin_topics = SiteSetting.default_topics_automatic_unpin
     self.email_private_messages = SiteSetting.default_email_private_messages
+    self.email_previous_replies = SiteSetting.default_email_previous_replies
 
     self.enable_quoting = SiteSetting.default_other_enable_quoting
     self.external_links_in_new_tab = SiteSetting.default_other_external_links_in_new_tab
diff --git a/app/models/username_validator.rb b/app/models/username_validator.rb
index 1ef41e17efa..0dbae4bae6e 100644
--- a/app/models/username_validator.rb
+++ b/app/models/username_validator.rb
@@ -71,7 +71,7 @@ class UsernameValidator
   def username_first_char_valid?
     return unless errors.empty?
     if username[0] =~ /\W/
-      self.errors << I18n.t(:'user.username.must_begin_with_alphanumeric')
+      self.errors << I18n.t(:'user.username.must_begin_with_alphanumeric_or_underscore')
     end
   end
 
diff --git a/app/serializers/user_option_serializer.rb b/app/serializers/user_option_serializer.rb
index 440587a4d42..bf43b41a36f 100644
--- a/app/serializers/user_option_serializer.rb
+++ b/app/serializers/user_option_serializer.rb
@@ -13,7 +13,8 @@ class UserOptionSerializer < ApplicationSerializer
              :automatically_unpin_topics,
              :edit_history_public,
              :auto_track_topics_after_msecs,
-             :new_topic_duration_minutes
+             :new_topic_duration_minutes,
+             :email_previous_replies
 
 
   def include_edit_history_public?
diff --git a/app/services/user_updater.rb b/app/services/user_updater.rb
index b3b8e9031c7..3b24efff08f 100644
--- a/app/services/user_updater.rb
+++ b/app/services/user_updater.rb
@@ -20,7 +20,8 @@ class UserUpdater
     :automatically_unpin_topics,
     :digest_after_days,
     :new_topic_duration_minutes,
-    :auto_track_topics_after_msecs
+    :auto_track_topics_after_msecs,
+    :email_previous_replies
   ]
 
   def initialize(actor, user)
diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index 89a2331567c..b476120000c 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -627,6 +627,11 @@ en:
 
       website: "Web Site"
       email_settings: "Email"
+      email_previous_replies:
+        title: "Include previous replies"
+        unless_emailed: "unless previously sent"
+        always: "always"
+        never: "never"
       email_digests:
         title: "When I don't visit here, send an email digest of what's new:"
         daily: "daily"
diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index 5a4011301a5..e42d71a2adc 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -1240,6 +1240,7 @@ en:
     default_email_direct: "Send an email when someone quotes/replies to/mentions or invites the user by default."
     default_email_mailing_list_mode: "Send an email for every new post by default."
     default_email_always: "Send an email notification even when the user is active by default."
+    default_email_previous_replies: "Include previous replies in emails by default."
 
     default_other_new_topic_duration_minutes: "Global default condition for which a topic is considered new."
     default_other_auto_track_topics_after_msecs: "Global default time before a topic is automatically tracked."
@@ -1394,8 +1395,8 @@ en:
       characters: "must only include numbers, letters and underscores"
       unique: "must be unique"
       blank: "must be present"
-      must_begin_with_alphanumeric: "must begin with a letter or number or an underscore"
-      must_end_with_alphanumeric: "must end with a letter or number or an underscore"
+      must_begin_with_alphanumeric_or_underscore: "must begin with a letter, a number or an underscore"
+      must_end_with_alphanumeric: "must end with a letter or a number"
       must_not_contain_two_special_chars_in_seq: "must not contain a sequence of 2 or more special chars (.-_)"
       must_not_end_with_confusing_suffix: "must not end with a confusing suffix like .json or .png etc."
     email:
diff --git a/config/site_settings.yml b/config/site_settings.yml
index b95667162aa..b456e86ca8b 100644
--- a/config/site_settings.yml
+++ b/config/site_settings.yml
@@ -1061,6 +1061,9 @@ user_preferences:
   default_email_direct: true
   default_email_mailing_list_mode: false
   default_email_always: false
+  default_email_previous_replies:
+    enum: 'PreviousRepliesSiteSetting'
+    default: 1
 
   default_other_new_topic_duration_minutes:
     enum: 'NewTopicDurationSiteSetting'
diff --git a/db/migrate/20160225050320_add_email_previous_replies_to_user_options.rb b/db/migrate/20160225050320_add_email_previous_replies_to_user_options.rb
new file mode 100644
index 00000000000..5f9aec18a03
--- /dev/null
+++ b/db/migrate/20160225050320_add_email_previous_replies_to_user_options.rb
@@ -0,0 +1,5 @@
+class AddEmailPreviousRepliesToUserOptions < ActiveRecord::Migration
+  def change
+    add_column :user_options, :email_previous_replies, :integer, null: false, default: 1
+  end
+end
diff --git a/spec/mailers/user_notifications_spec.rb b/spec/mailers/user_notifications_spec.rb
index 947dd9a466b..a58c2d16f53 100644
--- a/spec/mailers/user_notifications_spec.rb
+++ b/spec/mailers/user_notifications_spec.rb
@@ -7,12 +7,12 @@ describe UserNotifications do
   describe "#get_context_posts" do
     it "does not include hidden/deleted/user_deleted posts in context" do
       post1 = create_post
-      post2 = Fabricate(:post, topic: post1.topic, deleted_at: 1.day.ago)
-      post3 = Fabricate(:post, topic: post1.topic, user_deleted: true)
-      post4 = Fabricate(:post, topic: post1.topic, hidden: true)
-      post5 = Fabricate(:post, topic: post1.topic, post_type: Post.types[:moderator_action])
-      post6 = Fabricate(:post, topic: post1.topic, post_type: Post.types[:small_action])
-      post7 = Fabricate(:post, topic: post1.topic, post_type: Post.types[:whisper])
+      _post2 = Fabricate(:post, topic: post1.topic, deleted_at: 1.day.ago)
+      _post3 = Fabricate(:post, topic: post1.topic, user_deleted: true)
+      _post4 = Fabricate(:post, topic: post1.topic, hidden: true)
+      _post5 = Fabricate(:post, topic: post1.topic, post_type: Post.types[:moderator_action])
+      _post6 = Fabricate(:post, topic: post1.topic, post_type: Post.types[:small_action])
+      _post7 = Fabricate(:post, topic: post1.topic, post_type: Post.types[:whisper])
       last  = Fabricate(:post, topic: post1.topic)
 
       # default is only post #1
@@ -21,6 +21,26 @@ describe UserNotifications do
       tu = TopicUser.new(topic: post1.topic, user: build(:moderator))
       expect(UserNotifications.get_context_posts(last, tu).count).to eq(2)
     end
+
+    it "allows users to control context" do
+      post1 = create_post
+      _post2  = Fabricate(:post, topic: post1.topic)
+      post3  = Fabricate(:post, topic: post1.topic)
+
+      user = Fabricate(:user)
+      TopicUser.change(user.id, post1.topic_id, last_emailed_post_number: 1)
+      topic_user = TopicUser.find_by(user_id: user.id, topic_id: post1.topic_id)
+      # to avoid reloads after update_columns
+      user = topic_user.user
+      expect(UserNotifications.get_context_posts(post3, topic_user).count).to eq(1)
+
+      user.user_option.update_columns(email_previous_replies: UserOption.previous_replies_type[:never])
+      expect(UserNotifications.get_context_posts(post3, topic_user).count).to eq(0)
+
+      user.user_option.update_columns(email_previous_replies: UserOption.previous_replies_type[:always])
+      expect(UserNotifications.get_context_posts(post3, topic_user).count).to eq(2)
+
+    end
   end
 
   describe ".signup" do