title: Does asynctask not run parellel with main thread
body: <p>I read a post about asynctask <a href="http://www.vogella.com/tutorials/AndroidBackgroundProcessing/article.html" rel="nofollow">here</a>
  that says to execute it in parellel with main thread use executeOnExecutor method of this class. I thought asynctask to already run in parellel.
  Can someone explain this for me?</p>