This is sort of a theoretical question, however, I need to add file sharing capabilities to my web socket powered chat application. I could use a service like Amazon S3 to u
To allow files to be shared without the need to upload it to the server, (i.e Coworkers) you can now use the WebRTC DataChannel API, to create a peer to peer connection.
Here's an example of a project that uses only Web Sockets and the javascript File API for transferring files: http://www.github.com/thirtysixthspan/waterunderice