title: RESTful: bidirectional communication
body: <p>I was wondering if it is possible to have a RESTful web service and a bidirectional communication with the clients and server.</p>
  
  <p>In my case the state on the server can change, so the server should send a message to the clients to update themself. Perhaps that's totally against the RESTful idea.</p>
  
  <p>Can I AJAX help me with this issue?</p>
  
  <p>Thanks!</p>