title: what is STUN stun.l.google.com:19302 used for
body: <p>I'm looking at the <code>webrtc.html</code> and <code>peerconnection_server</code> demo, and it is working fine between two Chrome browsers.
  My question is, what exactly is the first param of webkitPeerConnection ?</p>
  
  <pre><code>pc = new webkitPeerConnection("STUN stun.l.google.com:19302", onSignalingMessage);
  </code></pre>
  
  <p>Is it a third party STUN server given by Google for demo purpose ?
  If, in my JavaScript code, I replace <code>"stun.l.google.com:19302"</code> by <code>"toto"</code>, I'm still able to make video calls.
  But as I'm on the same subnet, this can be explainable...</p>