diff --git a/app/views/content_viewer/_comment.rhtml b/app/views/content_viewer/_comment.rhtml
index 5827f61..8e8aee3 100644
--- a/app/views/content_viewer/_comment.rhtml
+++ b/app/views/content_viewer/_comment.rhtml
@@ -1,14 +1,17 @@
-<div class="article-comment<%=
-     ' comment-from-owner' if ( @page.profile.name == comment.author.name ) %>">
-  <%= link_to content_tag( 'span', comment.author.name() ), comment.author.url,
-      :class => 'comment-picture',
-      :style => 'background-image:url(%s)' % profile_icon(comment.author, :minor) %>
+<div class="article-comment<%= ' comment-from-owner' if ( comment.author && (@page.profile.name == comment.author.name) ) %>">
+  <% if comment.author %>
+    <%= link_to content_tag( 'span', comment.author.name() ), comment.author.url,
+        :class => 'comment-picture',
+        :style => 'background-image:url(%s)' % profile_icon(comment.author, :minor) %>
+  <% else %>
+    <%# unauthenticated user: display default icon %>
+    <%= content_tag('span', '&nbsp;', :class => 'comment-picture', :style => 'background-image: url(/images/icons-app/user_icon_size-minor.png)' )%>
+  <% end %>
+
   <h4><%= comment.title %></h4>
   <div class="comment-info">
     <%= _('By %{author} on %{date}') % {
-        :author => link_to(
-           (comment.author ? comment.author.identifier : comment.name),
-            comment.author.url),
+        :author => comment.author ? link_to(comment.author.name, comment.author.url) : content_tag('u', comment.name),
         :date => show_time(comment.created_on) } %>
   </div>
   <div class="comment-text">
--
libgit2 0.21.2