[JohanE]

It's all built on node.js. We used rails before to handle user accounts and static pages but realized we could make it all with node.js and MongoDB instead with some cool template language. :)

[swanson]

Are you using a library for the user stuff in mongo/node, if you don't mind me asking? I haven't found anything that seems better than devise/cancan.

[JohanE]

We've built a lot on our own. Maybe Senchalabs Connect can help you, otherwise check https://github.com/joyent/node/wiki/modules. Don't know if it's better than devise/cancan though.

[Omni5cience]

Devise and Cancan are User Authentication middleware for Rails

Check out https://github.com/ciaranj/connect-auth I can't vouch for the effectiveness, but it seems to be under active development.