title: Clarification of the exact function of NSNotificationCenter
body: <p>I'm still picking up ObjC and I'm just trying to make sure I understand the concept of <code>NSNotification</code>s <em>fully</em>:</p>
  
  <p>The <code>[NSNotificationCenter defaultCenter]</code> is a stationary object which is <strong>not</strong> the <em>sender</em> or the <em>receiver</em>. It merely <em>routes</em> an <code>NSNotification</code>, but in no way, shape, or form handles the event (by default).</p>
  
  <p>Is that correct?</p>
  
  <p><em>Theory:</em><br>
  Would that allow an <code>AppDelegate</code> to <em>push</em> a notification to the <code>defaultCenter</code> and have something further on in the responder chain / display list (e.g., <code>UITableViewCell</code>) pick up on the action?</p>