BUGFIX: use previous_visit_at instead of last_seen_at to determine the best period to display in the top summary

app/controllers/list_controller.rb

@@ -208,7 +208,7 @@ class ListController < ApplicationController
     topic_query = TopicQuery.new(current_user, options)
 
     if current_user.present?
-      periods = [best_period_for(current_user.last_seen_at)]
+      periods = [best_period_for(current_user.previous_visit_at)]
     else
       periods = TopTopic.periods
     end
@@ -219,6 +219,7 @@ class ListController < ApplicationController
   end
 
   def best_period_for(date)
+    date ||= 1.year.ago
     return :yearly  if date < 180.days.ago
     return :monthly if date <  35.days.ago
     return :weekly  if date <   8.days.ago

app/models/user.rb

@@ -607,8 +607,7 @@ class User < ActiveRecord::Base
   private
 
   def previous_visit_at_update_required?(timestamp)
-    seen_before? &&
-      (last_seen_at < (timestamp - SiteSetting.previous_visit_timeout_hours.hours))
+    seen_before? && last_seen_at < (timestamp - SiteSetting.previous_visit_timeout_hours.hours)
   end
 
   def update_previous_visit(timestamp)

config/locales/client.en.yml

@@ -1127,7 +1127,7 @@ en:
         today: "Today"
         other_periods: "dig into other periods"
         redirect_reasons:
-          new_user: "Welcome! As a new visitor, we thought you might like to start with this list of the top discussion topics in the last year."
+          new_user: "Welcome! As a new visitor, we thought you might like to start with this list of the top discussion topics."
           not_seen_in_a_month: "Welcome back! We haven't seen you in a while. These are the top discussion topics since you've been away."
 
     browser_update: 'Unfortunately, <a href="http://www.discourse.org/faq/#browser">your browser is too old to work on this Discourse forum</a>. Please <a href="http://browsehappy.com">upgrade your browser</a>.'