title: How to build a distributed chat website on Azure without polling?
body: <p>I need to make a website on Azure that has a simple chat feature-where one client can send a message to another waiting client</p>
  
  <p>I'm not sure how to develop this without polling ("do you have a message for me") </p>
  
  <p>I'm assuming the trick is to have one client send an async (blocking) call to the webserver,  then unblock the call when a new message arrives </p>
  
  <p>... If I weren't in a distributed environment (one webserver) ,  this would be pretty easy to implement,  but when multiple frontend servers are involved I'm not sure the best way to coordinate </p>
  
  <p>I'm flexible in pretty much all ways,  but it needs to run on Azure.   I can use sql azure, a Azure queue,  etc</p>
  
  <p>Tips?  </p>