remove broken links for implementors

This doesn't attempt to update the list with current implementors, but just removes old links that are no longer active.

Fixes #9, #11
Ref #2

index.html

@@ -34,18 +34,10 @@
     <p>
       The Activity Streams format has already been adopted by
       BBC,
-      <a href="http://blog.gnip.com/activity-streams/" title="Activity Streams - Gnip">Gnip</a>,
-      <a href="http://code.google.com/apis/buzz/" title="Google Buzz API - Google Code">Google Buzz</a>
-      <a href="http://www.readwriteweb.com/archives/gowalla_adds_real-time_feeds_and_activity_streams.php">Gowalla</a>,
       <a href="http://www.ibm.com">IBM</a>,
-      <a href="http://wiki.developer.myspace.com/index.php?title=Standards_for_Activity_Streams">MySpace</a>,
-      <a href="http://dev.opera.com/libraries/activitystream/">Opera</a>,
-      <a href="http://socialcast.com">Socialcast</a>,
       <a href="http://blog.superfeedr.com/activity/pubsubhubbub/streams/activity-streams/" title="Superfeedr Blog : Activity Streams">Superfeedr</a>,
-      <a href="https://wiki.activitystrea.ms/TypePad-Activity-Streams">TypePad</a>,
-      <a href="http://windowsteamblog.com/windows_live/b/developer/archive/2010/06/28/social-distribution.aspx" title="Social Distribution">Windows Live</a>,
-      <a href="http://yiid.com/" title="Your Internet ID | yiid - (Simplify your community life)">YIID</a>, and
-      <a href="http://wiki.activitystrea.ms/Implementors">many others</a>.
+      <a href="http://wiki.activitystrea.ms/TypePad-Activity-Streams">TypePad</a>,
+      and <a href="http://wiki.activitystrea.ms/Implementors">many others</a>.
     </p>
 
     <p>