title: Do I use NSNotifications too much
body: <p>I recently found the benefit of using <code>NSNotifications</code> when making very custom layouts in my iOS app. I now use them to send data round instead of using delegates. For example I have a <code>UIScrollView</code> in one controller, which varies the alpha of a picture in another <code>view controller</code>, so I just send notifications as the scroll view scrolls, e.g. </p>
  
  <pre><code>func scrollViewDidScroll(scrollView: UIScrollView) {
  
          let userInfo = ["ScrollView":scrollView]
          NSNotificationCenter.defaultCenter().postNotificationName("scrollViewScrolled", object: self, userInfo: userInfo)
  }
  </code></pre>
  
  <p>And observe for this in the other view controller. I know that <code>NSNotifications</code> aren't expensive on performance, but with the extent that I use them, and the data I send with them, I wondered whether it would be considered bad practice.</p>