Looks like an advertorial. No mention of socket.io and praise for a commercial solution that I didn't know after almost two years working with websockets.
By the way, at the moment I'm using Python's Twisted with a simple wrapper called txWS: https://github.com/MostAwesomeDude/txWS
I'm not a big fan of socket.IO, seems too complex for my needs. I was quite happy to discover txWS, it's literally one more function call and you can just write ordinary Twisted code with no changes, which is a relief.
Edit: I'm tempted to purchase websockets.co...
Besides support in recent browsers, anything else inaccurate in it?