title: Real-time update: the notifications' contain uid and id, but the value are same
body: <p>The notifications I received from Facebook are all like the following:</p>
  
  <pre><code>{"object":"user","entry":[{"uid":"100002366898088","id":"100002366898088","time":1314270539,"changed_fields":["feed"]}]}
  </code></pre>
  
  <p>I am wondering what does the "id" used for? Shouldn't it be the changed feed's id? Why it always same with the uid?</p>