title: Detect Change in UILabel Text
body: <p>Is it possible to set a Notification for when a UILabel's text property is changed?  I tried the one used for UITextFields when I couldn't find one for a UILabel, but it didn't work.</p>
  
  <pre><code> [[NSNotificationCenter defaultCenter]
   addObserver:self
   selector:@selector(posttosocial)
   name:UITextFieldTextDidChangeNotification
   object:nowplaying];
  </code></pre>