title: Actor model to replace the threading model?
body: <p>I read a chapter in a book (Seven languages in Seven Weeks by Bruce A. Tate) about Matz (Inventor of Ruby) saying that 'I would remove the thread and add actors, or some other more advanced concurrency features'. </p>
  
  <ul>
  <li>Why and how an actor model can be an advanced concurrency model that replaces the threading?</li>
  <li>What other models are the 'advanced concurrency model'?</li>
  </ul>