Take a look at TogetherJS

Want to add real-time collaboration to your Web application? Mozilla’s TogetherJS is worth a look.

When Tim Berners-Lee invented the World Wide Web more than 20 years ago, he did it in the hopes that physicists would be able to collaborate easily with one another over the Internet. Since then, the Web has grown and morphed into a new medium that handles everything from newspapers to finance to supermarkets.