[dingaling]

I'm assuming it uses WebRTC; it won't let me into the site past the front page as I don't use Chrome.

Which is sad, since the Mozilla and Chrome teams work closely on developing WebRTC and ensuring compatibility.

Edit: found some more info in the source of that page. This is their configuration guide:

1. Open the URL chrome://flags the latest version of Google Chrome.

2. Scroll to the bottom of the page and enable "Enable screen capture support in getUserMedia()

3. Restart browser - that's it

So, yes, WebRTC.