Merge pull request #418 from dret/patch-4

abstract need a little love

Author: rhiaro

vocabulary/index.html

@@ -110,7 +110,7 @@
 
   <section id="abstract">
     <p>
-      This specification describes the Activity vocabulary.
+      This specification describes the Activity vocabulary. It is intended to be used in the context of the ActivityStreams 2.0 format and provides a foundational vocabulary for activity structures, and specific activity types.
     </p>
 
     <section id="authorsnote" class="informative">