title: What are the differences and useage patterns for dispatchers in Akka 2?
body: <p>I've trouble understanding the differences and recommended usage of the <a href="http://doc.akka.io/docs/akka/current/scala/dispatchers.html" rel="nofollow">dispatchers in Akka 2</a>. I think I understand how the <a href="http://doc.akka.io/api/akka/current/#akka.dispatch.BalancingDispatcher" rel="nofollow">BalancingDispatcher</a> and the <a href="http://doc.akka.io/api/akka/current/#akka.testkit.CallingThreadDispatcher" rel="nofollow">CallingThreadDispatcher</a> behave but I have no idea about the <a href="http://doc.akka.io/api/akka/current/#akka.dispatch.Dispatcher" rel="nofollow">Dispatcher</a> and <a href="http://doc.akka.io/api/akka/current/#akka.dispatch.PinnedDispatcher" rel="nofollow">PinnedDispatcher</a>.</p>
  
  <p>I don't understand the concepts of <code>Sharability</code> and <code>Bulkheading</code>, either.</p>