Support for crawling topic links

app/assets/javascripts/discourse/helpers/application_helpers.js

@@ -385,3 +385,25 @@ Handlebars.registerHelper('customHTML', function(name, contextString, options) {
 Ember.Handlebars.registerBoundHelper('humanSize', function(size) {
   return new Handlebars.SafeString(I18n.toHumanSize(size));
 });
+
+/**
+  Renders the domain for a link if it's not internal and has a title.
+
+  @method link-domain
+  @for Handlebars
+**/
+Handlebars.registerHelper('link-domain', function(property, options) {
+  var link = Em.get(this, property, options);
+  if (link) {
+    var internal = Em.get(link, 'internal'),
+        hasTitle = (!Em.isEmpty(Em.get(link, 'title')));
+    if (hasTitle && !internal) {
+      var domain = Em.get(link, 'domain');
+      if (!Em.isEmpty(domain)) {
+        var s = domain.split('.');
+        domain = s[s.length-2] + "." + s[s.length-1];
+        return new Handlebars.SafeString("<span class='domain'>(" + domain + ")</span>");
+      }
+    }
+  }
+});

app/assets/javascripts/discourse/templates/components/topic-map.js.handlebars

@@ -65,6 +65,7 @@
                 {{#if title}}{{title}}{{else}}{{shortenUrl url}}{{/if}}
                 {{#unless internal}}<i class='fa fa-external-link'></i>{{/unless}}
               </a>
+              {{link-domain this}}
             </li>
           {{/groupedEach}}
         </ul>