title: jQuery deferreds and promises - .then() vs .done()
body: <p>I've been reading about jQuery deferreds and promises and I can't see the difference between using <code>.then()</code> &amp; <code>.done()</code> for successful callbacks. I know <a href="http://www.erichynds.com/jquery/using-deferreds-in-jquery/" rel="noreferrer">Eric Hynds</a> mentions that <code>.done()</code> and <code>.success()</code> map to the same functionality but I'm guessing so does <code>.then()</code> as all the callbacks are all invoked on a completion of a successful operation. </p>
  
  <p>Can anyone please enlighten me to the correct usage?</p>