diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index d00636d4c7..64385359b7 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -54,7 +54,8 @@ module ApplicationHelper
       name = h(user.name(options[:format]))
       if user.active? || (User.current.admin? && user.logged?)
         only_path = options[:only_path].nil? ? true : options[:only_path]
-        link_to name, user_url(user, :only_path => only_path), :class => user.css_classes
+        css_classes = options[:class] ? "#{user.css_classes} #{options[:class]}" : user.css_classes
+        link_to name, user_url(user, :only_path => only_path), :class => css_classes
       else
         name
       end
@@ -990,9 +991,6 @@ module ApplicationHelper
               if p = Project.visible.find_by_id(oid)
                 link = link_to_project(p, {:only_path => only_path}, :class => 'project')
               end
-            when 'user'
-              u = User.visible.find_by(:id => oid, :type => 'User')
-              link = link_to_user(u, :only_path => only_path) if u
             end
           elsif sep == ':'
             name = remove_double_quotes(identifier)
@@ -1051,14 +1049,14 @@ module ApplicationHelper
               if p = Project.visible.where("identifier = :s OR LOWER(name) = :s", :s => name.downcase).first
                 link = link_to_project(p, {:only_path => only_path}, :class => 'project')
               end
-            when 'user'
-              u = User.visible.find_by("LOWER(login) = :s AND type = 'User'", :s => name.downcase)
-              link = link_to_user(u, :only_path => only_path) if u
             end
-          elsif sep == "@"
-            name = remove_double_quotes(identifier)
-            u = User.visible.find_by("LOWER(login) = :s AND type = 'User'", :s => name.downcase)
-            link = link_to_user(u, :only_path => only_path) if u
+          end
+          if link.nil? && $~
+            user = User.mentioned_user($~.named_captures.symbolize_keys)
+            if user
+              css_classes = (user.notify_mentioned_user?(obj) ? 'notified' : nil)
+              link = link_to_user(user, :only_path => only_path, :class => css_classes)
+            end
           end
         end
         (leading + (link || "#{project_prefix}#{prefix}#{repo_prefix}#{sep}#{identifier}#{comment_suffix}"))
diff --git a/app/models/document.rb b/app/models/document.rb
index 5be0a61c7c..2ec1535b78 100644
--- a/app/models/document.rb
+++ b/app/models/document.rb
@@ -63,7 +63,7 @@ class Document < ActiveRecord::Base
   end
 
   def notified_users
-    project.notified_users.reject {|user| !visible?(user)}
+    project.notified_users.select {|user| user.allowed_to_view_notify_target?(self) }
   end
 
   private
diff --git a/app/models/issue.rb b/app/models/issue.rb
index cd13fd3c55..f8ed3223d1 100644
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -1040,8 +1040,7 @@ class Issue < ActiveRecord::Base
     notified += project.notified_users
     notified.uniq!
     # Remove users that can not view the issue
-    notified.reject! {|user| !visible?(user)}
-    notified
+    notified.select {|user| user.allowed_to_view_notify_target?(self)}
   end
 
   # Returns the email addresses that should be notified
diff --git a/app/models/journal.rb b/app/models/journal.rb
index 0077b548dc..acfe97c9c4 100644
--- a/app/models/journal.rb
+++ b/app/models/journal.rb
@@ -143,10 +143,7 @@ class Journal < ActiveRecord::Base
 
   def notified_users
     notified = journalized.notified_users
-    if private_notes?
-      notified = notified.select {|user| user.allowed_to?(:view_private_notes, journalized.project)}
-    end
-    notified
+    notified.select{ |u| u.allowed_to_view_notify_target?(self) }
   end
 
   def recipients
diff --git a/app/models/mailer.rb b/app/models/mailer.rb
index 5ef10c1d7e..fd9955f69c 100644
--- a/app/models/mailer.rb
+++ b/app/models/mailer.rb
@@ -92,6 +92,7 @@ class Mailer < ActionMailer::Base
   #   Mailer.deliver_issue_add(issue)
   def self.deliver_issue_add(issue)
     users = issue.notified_users | issue.notified_watchers
+    users |= mentioned_users(issue.description, issue)
     users.each do |user|
       issue_add(user, issue).deliver_later
     end
@@ -126,6 +127,7 @@ class Mailer < ActionMailer::Base
   #   Mailer.deliver_issue_edit(journal)
   def self.deliver_issue_edit(journal)
     users  = journal.notified_users | journal.notified_watchers
+    users |= mentioned_users(journal.notes, journal)
     users.select! do |user|
       journal.notes? || journal.visible_details(user).any?
     end
@@ -151,6 +153,7 @@ class Mailer < ActionMailer::Base
   #   Mailer.deliver_document_added(document, author)
   def self.deliver_document_added(document, author)
     users = document.notified_users
+    users |= mentioned_users(document.description, document)
     users.each do |user|
       document_added(user, document, author).deliver_later
     end
@@ -219,6 +222,7 @@ class Mailer < ActionMailer::Base
   #   Mailer.deliver_news_added(news)
   def self.deliver_news_added(news)
     users = news.notified_users | news.notified_watchers_for_added_news
+    users |= mentioned_users(news.description, news)
     users.each do |user|
       news_added(user, news).deliver_later
     end
@@ -246,6 +250,7 @@ class Mailer < ActionMailer::Base
   def self.deliver_news_comment_added(comment)
     news = comment.commented
     users = news.notified_users | news.notified_watchers
+    users |= mentioned_users(comment.content, news)
     users.each do |user|
       news_comment_added(user, comment).deliver_later
     end
@@ -273,6 +278,7 @@ class Mailer < ActionMailer::Base
     users  = message.notified_users
     users |= message.root.notified_watchers
     users |= message.board.notified_watchers
+    users |= mentioned_users(message.content, message)
 
     users.each do |user|
       message_posted(user, message).deliver_later
@@ -300,6 +306,7 @@ class Mailer < ActionMailer::Base
   #   Mailer.deliver_wiki_content_added(wiki_content)
   def self.deliver_wiki_content_added(wiki_content)
     users = wiki_content.notified_users | wiki_content.page.wiki.notified_watchers
+    users |= mentioned_users(wiki_content.text, wiki_content)
     users.each do |user|
       wiki_content_added(user, wiki_content).deliver_later
     end
@@ -331,6 +338,7 @@ class Mailer < ActionMailer::Base
     users  = wiki_content.notified_users
     users |= wiki_content.page.notified_watchers
     users |= wiki_content.page.wiki.notified_watchers
+    users |= mentioned_users(wiki_content.text, wiki_content)
 
     users.each do |user|
       wiki_content_updated(user, wiki_content).deliver_later
@@ -760,5 +768,16 @@ class Mailer < ActionMailer::Base
     @references_objects ||= []
     @references_objects << object
   end
+
+  def self.mentioned_users(text, obj)
+    users = []
+    return users if text.blank?
+    text.scan(ApplicationHelper::LINKS_RE) do |_|
+      target = User.mentioned_user($~.named_captures.symbolize_keys)
+      next if target.blank? || users.include?(target)
+      users << target if target.notify_mentioned_user?(obj)
+    end
+    users
+  end
 end
 
diff --git a/app/models/message.rb b/app/models/message.rb
index c466f66be6..4baaf1f9f9 100644
--- a/app/models/message.rb
+++ b/app/models/message.rb
@@ -105,7 +105,7 @@ class Message < ActiveRecord::Base
   end
 
   def notified_users
-    project.notified_users.reject {|user| !visible?(user)}
+    project.notified_users.select {|user| user.allowed_to_view_notify_target?(self) }
   end
 
   private
diff --git a/app/models/news.rb b/app/models/news.rb
index 02418107c9..913d3d1159 100644
--- a/app/models/news.rb
+++ b/app/models/news.rb
@@ -56,7 +56,7 @@ class News < ActiveRecord::Base
   end
 
   def notified_users
-    project.users.select {|user| user.notify_about?(self) && user.allowed_to?(:view_news, project)}
+    project.users.select {|user| user.notify_about?(self) && user.allowed_to_view_notify_target?(self)}
   end
 
   def recipients
diff --git a/app/models/user.rb b/app/models/user.rb
index 698b1bac9b..ca3af2ada2 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -797,6 +797,47 @@ class User < Principal
     RequestStore.store[:current_user] ||= User.anonymous
   end
 
+  # Return the mentioned user to based on the match data
+  #  of ApplicationHelper::LINKS_RE.
+  #     user:jsmith -> Link to user with login jsmith
+  #     @jsmith -> Link to user with login jsmith
+  #     user#2 -> Link to user with id 2
+  def self.mentioned_user(match_data)
+    return nil if match_data[:esc]
+    sep = match_data[:sep1] || match_data[:sep2] || match_data[:sep3] || match_data[:sep4]
+    identifier = match_data[:identifier1] || match_data[:identifier2] || match_data[:identifier3]
+    prefix = match_data[:prefix]
+    if (sep == '#' || sep == '##') && prefix == 'user'
+      User.visible.find_by(:id => identifier.to_i, :type => 'User')
+    elsif sep == '@' || (sep == ':' && prefix == 'user')
+      name = identifier.gsub(%r{^"(.*)"$}, "\\1")
+      User.find_by_login(CGI.unescapeHTML(name).downcase)
+    end
+  end
+
+  # Return true if notify the mentioned user.
+  def notify_mentioned_user?(object)
+    self.active? &&
+      self.mail.present? &&
+      self.mail_notification.present? && self.mail_notification != 'none' &&
+      self.allowed_to_view_notify_target?(object)
+  end
+
+  # Return true if the user is allowed to view the notify target.
+  def allowed_to_view_notify_target?(object)
+    case object
+    when Journal
+      self.allowed_to_view_notify_target?(object.journalized) &&
+        (!object.private_notes? || self.allowed_to?(:view_private_notes, object.journalized.project))
+    when Comment
+      self.allowed_to_view_notify_target?(object.commented)
+    when nil
+      false
+    else
+      object.visible?(self)
+    end
+  end
+
   # Returns the anonymous user.  If the anonymous user does not exist, it is created.  There can be only
   # one anonymous user per database.
   def self.anonymous
diff --git a/app/models/wiki_content.rb b/app/models/wiki_content.rb
index 7bda26009c..01d95aaf35 100644
--- a/app/models/wiki_content.rb
+++ b/app/models/wiki_content.rb
@@ -53,7 +53,7 @@ class WikiContent < ActiveRecord::Base
   end
 
   def notified_users
-    project.notified_users.reject {|user| !visible?(user)}
+    project.notified_users.select {|user| user.allowed_to_view_notify_target?(self) }
   end
 
   # Returns the mail addresses of users that should be notified
diff --git a/test/helpers/application_helper_test.rb b/test/helpers/application_helper_test.rb
index a524c91b82..91463ebc13 100644
--- a/test/helpers/application_helper_test.rb
+++ b/test/helpers/application_helper_test.rb
@@ -1562,6 +1562,12 @@ RAW
     assert_equal ::I18n.t(:label_user_anonymous), t
   end
 
+  def test_link_to_user_with_class_name_should_include_class
+    user = User.find(2)
+    result = link_to("John Smith", "/users/2", :class => "user active test")
+    assert_equal result, link_to_user(user, :class => 'test')
+  end
+
   def test_link_to_attachment
     a = Attachment.find(3)
     assert_equal '<a href="/attachments/3">logo.gif</a>',
diff --git a/test/unit/mailer_test.rb b/test/unit/mailer_test.rb
index 51fc001f9d..59758df8a4 100644
--- a/test/unit/mailer_test.rb
+++ b/test/unit/mailer_test.rb
@@ -365,6 +365,30 @@ class MailerTest < ActiveSupport::TestCase
     assert_include 'dlopper@somenet.foo', recipients
   end
 
+  def test_issue_added_should_notify_mentioned_users
+    # Non-public project issue
+    issue = Issue.find(4)
+    # Developer
+    user = User.find(8)
+    assert issue.visible?(user)
+
+    # Notify mentioned users.
+    ["user##{user.id}", "@#{user.login}", "user:#{user.login}"].each do |description|
+      issue.update(:description => description)
+      ActionMailer::Base.deliveries.clear
+      Mailer.deliver_issue_add(issue)
+      assert_include user.mail, recipients
+    end
+
+    # Do not notify unauthorized mentioned users.
+    Role.find(2).remove_permission!(:view_issues)
+    assert_not issue.visible?(user.reload)
+    issue.update(:description => "user##{user.id}")
+    ActionMailer::Base.deliveries.clear
+    Mailer.deliver_issue_add(issue)
+    assert_not_include user.mail, recipients
+  end
+
   def test_issue_add_should_send_mail_to_all_user_email_address
     EmailAddress.create!(:user_id => 3, :address => 'otheremail@somenet.foo')
     issue = Issue.find(1)
@@ -534,6 +558,29 @@ class MailerTest < ActiveSupport::TestCase
     end
   end
 
+  def test_issue_edit_should_notify_mentioned_users
+    # Non-public project journal
+    issue = Issue.find(4)
+    journal = Journal.generate!(:notes => '', :details => [JournalDetail.new], :journalized => issue)
+    # Developer
+    user = User.find(8)
+
+    # Notify mentioned users.
+    ["user##{user.id}", "@#{user.login}", "user:#{user.login}"].each do |note|
+      journal.update(:notes => note)
+      Mailer.deliver_issue_edit(journal)
+      assert_include user.mail, recipients
+      ActionMailer::Base.deliveries.clear
+    end
+
+    # Do not notify mentioned users without view_private_notes permission and journal is private.
+    Role.find(2).remove_permission!(:view_private_notes)
+    journal.update(:notes => "user##{user.id}", :private_notes => true)
+    Mailer.deliver_issue_edit(journal)
+    assert_not_include user.mail, recipients
+    ActionMailer::Base.deliveries.clear
+  end
+
   def test_version_file_added
     attachements = [ Attachment.find_by_container_type('Version') ]
     assert Mailer.deliver_attachments_added(attachements)
@@ -565,6 +612,53 @@ class MailerTest < ActiveSupport::TestCase
     assert_not_include user2.mail, recipients
   end
 
+  def test_news_added_should_notify_mentioned_users
+    project = Project.find(1)
+    news = project.news.first
+    user = User.find(8) # non member
+    assert news.visible?(user)
+
+    # Notify mentioned users.
+    ["user##{user.id}", "@#{user.login}", "user:#{user.login}"].each do |description|
+      news.update(:description => description)
+      Mailer.deliver_news_added(news)
+      assert_include user.mail, recipients
+      ActionMailer::Base.deliveries.clear
+    end
+
+    # Do not notify unauthorized mentioned users.
+    Role.non_member.remove_permission!(:view_news)
+    assert_not news.visible?(user.reload)
+    news.update(:description => "user##{user.id}")
+    Mailer.deliver_news_added(news)
+    assert_not_include user.mail, recipients
+    ActionMailer::Base.deliveries.clear
+  end
+
+  def test_news_comment_added_should_notify_mentioned_users
+    project = Project.find(1) # public project
+    news = project.news.first
+    comment = news.comments.first
+    user = User.find(8) # non member
+    assert news.visible?(user)
+
+    # Notify mentioned users.
+    ["user##{user.id}", "@#{user.login}", "user:#{user.login}"].each do |text|
+      comment.update(:content => text)
+      Mailer.deliver_news_comment_added(comment)
+      assert_include user.mail, recipients
+      ActionMailer::Base.deliveries.clear
+    end
+
+    # Do not notify unauthorized mentioned users.
+    Role.non_member.remove_permission!(:view_news)
+    assert_not news.visible?(user.reload)
+    comment.update(:content => "user##{user.id}")
+    Mailer.deliver_news_comment_added(comment)
+    assert_not_include user.mail, recipients
+    ActionMailer::Base.deliveries.clear
+  end
+
   def test_wiki_content_added
     content = WikiContent.find(1)
     assert_difference 'ActionMailer::Base.deliveries.size', 2 do
@@ -577,6 +671,30 @@ class MailerTest < ActiveSupport::TestCase
     end
   end
 
+  def test_wiki_content_added_should_notify_mentioned_users
+    # Non-public project wiki_content
+    project = Project.find(2)
+    wiki_content = project.wiki.pages.first.content
+    user = User.find(8)
+    assert wiki_content.visible?(user)
+
+    # Notify mentioned users.
+    ["user##{user.id}", "@#{user.login}", "user:#{user.login}"].each do |text|
+      wiki_content.update(:text => text)
+      Mailer.deliver_wiki_content_added(wiki_content)
+      assert_include user.mail, recipients
+      ActionMailer::Base.deliveries.clear
+    end
+
+    # Do not notify unauthorized mentioned users.
+    Role.find(2).remove_permission!(:view_wiki_pages)
+    assert_not wiki_content.visible?(user.reload)
+    wiki_content.update(:text => "user##{user.id}")
+    Mailer.deliver_wiki_content_added(wiki_content)
+    assert_not_include user.mail, recipients
+    ActionMailer::Base.deliveries.clear
+  end
+
   def test_wiki_content_updated
     content = WikiContent.find(1)
     assert Mailer.deliver_wiki_content_updated(content)
@@ -946,6 +1064,56 @@ class MailerTest < ActiveSupport::TestCase
       Mailer.email_addresses(User.find(2)).sort
   end
 
+  def test_document_added_should_notify_mentioned_users
+    # Non-public project document
+    project = Project.find(2)
+    project.enable_module!(:documents)
+    document = Document.generate!(:project => project)
+    # Developer
+    user = User.find(8)
+    assert document.visible?(user)
+
+    # Notify mentioned users.
+    ["user##{user.id}", "@#{user.login}", "user:#{user.login}"].each do |description|
+      document.update(:description => description)
+      Mailer.deliver_document_added(document, User.first)
+      assert_include user.mail, recipients
+      ActionMailer::Base.deliveries.clear
+    end
+
+    # Do not notify unauthorized mentioned users.
+    Role.find(2).remove_permission!(:view_documents)
+    assert_not document.visible?(user.reload)
+    document.update(:description => "user##{user.id}")
+    Mailer.deliver_document_added(document, User.first)
+    assert_not_include user.mail, recipients
+    ActionMailer::Base.deliveries.clear
+  end
+
+  def test_message_posted_should_notify_mentioned_users
+    # Non-public project message
+    project = Project.find(2)
+    message = project.boards.first.messages.first
+    user = User.find(8)
+    assert message.visible?(user)
+
+    # Notify mentioned users.
+    ["user##{user.id}", "@#{user.login}", "user:#{user.login}"].each do |text|
+      message.update(:content => text)
+      Mailer.deliver_message_posted(message)
+      assert_include user.mail, recipients
+      ActionMailer::Base.deliveries.clear
+    end
+
+    # Do not notify unauthorized mentioned users.
+    Role.find(2).remove_permission!(:view_messages)
+    assert_not message.visible?(user.reload)
+    message.update(:content => "user##{user.id}")
+    Mailer.deliver_message_posted(message)
+    assert_not_include user.mail, recipients
+    ActionMailer::Base.deliveries.clear
+  end
+
   private
 
   # Returns an array of email addresses to which emails were sent
diff --git a/test/unit/user_test.rb b/test/unit/user_test.rb
index 5ae17508f0..9065c76e50 100644
--- a/test/unit/user_test.rb
+++ b/test/unit/user_test.rb
@@ -461,6 +461,69 @@ class UserTest < ActiveSupport::TestCase
     assert_nil changeset.reload.user_id
   end
 
+  def test_mentioned_user
+    # user#id
+    match_data = { :esc => nil,  :prefix => 'user', :sep1 => '#', :identifier1 => '1' }
+    assert_equal User.mentioned_user(match_data), User.find(1)
+
+    # user:login
+    match_data = { :esc => nil,  :prefix => 'user', :sep3 => ':', :identifier2 => 'admin' }
+    assert_equal User.mentioned_user(match_data), User.find_by_login('admin')
+
+    # @login
+    match_data = { :esc => nil,  :sep4 => '@', :identifier3 => 'admin' }
+    assert_equal User.mentioned_user(match_data), User.find_by_login('admin')
+  end
+
+  def test_notify_mentioned_user?
+    issue = Issue.first
+    user = User.find(2)
+    assert user.notify_mentioned_user?(issue)
+
+    user.roles_for_project(issue.project).first.remove_permission!(:view_issues)
+    assert_not user.reload.notify_mentioned_user?(issue)
+  end
+
+  def test_allowed_to_view_notify_target
+    issue = Issue.first
+    user = User.find(2)
+
+    assert issue.visible?(user)
+    assert user.allowed_to_view_notify_target?(issue)
+
+    user.roles_for_project(issue.project).first.remove_permission!(:view_issues)
+    user.reload
+    assert_not issue.visible?(user)
+    assert_not user.allowed_to_view_notify_target?(issue)
+  end
+
+  def test_allowed_to_view_notify_target_with_journal
+    journal = Journal.first
+    user = User.find(3)
+
+    assert journal.issue.visible?(user)
+    assert user.allowed_to_view_notify_target?(journal)
+
+    journal.update(:private_notes => true)
+    Role.find(2).remove_permission!(:view_private_note)
+    assert_not user.reload.allowed_to_view_notify_target?(journal)
+
+    journal.update(:private_notes => false)
+    Role.find(2).remove_permission!(:view_issues)
+    assert_not user.reload.allowed_to_view_notify_target?(journal)
+  end
+
+  def test_allowed_to_view_notify_target_with_comment
+    comment = Comment.first
+    user = User.find(3)
+
+    assert comment.commented.visible?(user)
+    assert user.allowed_to_view_notify_target?(comment)
+
+    Role.find(2).remove_permission!(:view_news)
+    assert_not user.reload.allowed_to_view_notify_target?(comment)
+  end
+
   def test_anonymous_user_should_not_be_destroyable
     assert_no_difference 'User.count' do
       assert_equal false, User.anonymous.destroy