diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 62685ec..d8dfb89 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -609,6 +609,10 @@ module ApplicationHelper
     url
   end
 
+  def gravatar_profile_url(email)
+    'http://www.gravatar.com/'+ Digest::MD5.hexdigest(email)
+  end
+
   attr_reader :environment
   def select_categories(object_name, title=nil, title_size=4)
     return nil if environment.enabled?(:disable_categories)
diff --git a/app/views/content_viewer/_comment.rhtml b/app/views/content_viewer/_comment.rhtml
index 22d8d10..1a9d895 100644
--- a/app/views/content_viewer/_comment.rhtml
+++ b/app/views/content_viewer/_comment.rhtml
@@ -11,14 +11,21 @@
         :title => comment.author_name
     %>
   <% else %>
-    <%# unauthenticated user: display gravatar icon %>
-    <% url_image, status_class = comment.author_id ? [comment.removed_user_image, 'icon-user-removed'] : [str_gravatar_url_for( comment.email, :size => 50 ), 'icon-user-unknown'] %>
-    <%= content_tag 'span', image_tag(url_image) +
-                            content_tag('span', comment.author_name, :class => 'comment-info') +
-                            content_tag('span', comment.message, :class => 'comment-user-status ' + status_class),
+    <% url_image, status_class = comment.author_id ?
+       [comment.removed_user_image, 'icon-user-removed'] :
+       [str_gravatar_url_for( comment.email, :size => 50, :d=>404 ), 'icon-user-unknown'] %>
+
+    <%= link_to(
+          image_tag(url_image, :onerror=>'gravatarCommentFailback(this)',
+                   'data-gravatar'=>str_gravatar_url_for(comment.email, :size=>50)) +
+          content_tag('span', comment.author_name, :class => 'comment-info') +
+          content_tag('span', comment.message,
+                             :class => 'comment-user-status ' + status_class),
+        gravatar_profile_url(comment.email),
+        :target => '_blank',
         :class => 'comment-picture',
         :title => '%s %s' % [comment.author_name, comment.message]
-    %>
+    )%>
   <% end %>
 
   <% comment_balloon do %>
diff --git a/public/javascripts/application.js b/public/javascripts/application.js
index a134af2..871d53d 100644
--- a/public/javascripts/application.js
+++ b/public/javascripts/application.js
@@ -681,6 +681,12 @@ function original_image_dimensions(src) {
   return { 'width' : img.width, 'height' : img.height };
 }
 
+function gravatarCommentFailback(img) {
+  var link = img.parentNode;
+  link.href = "http://www.gravatar.com";
+  img.src = img.getAttribute("data-gravatar");
+}
+
 jQuery(function() {
   jQuery("#ajax-form").before("<div id='ajax-form-loading-area' style='display:block;width:16px;height:16px;'></div>");
   jQuery("#ajax-form").before("<div id='ajax-form-message-area'></div>");
--
libgit2 0.21.2