Ok, it is not obvious from the video but it seemed that the chat functionality is built into your system and it seems like some JavaScript-based GUI similar to

Ok, it is not obvious from the video but it seemed that the chat functionality is built into your system and it seems like some JavaScript-based GUI similar to Meebo. It might be easier to let people copy/paste and send a link to each other via whatever chat they are already using. Implementing a chat system seems like a distraction here. Again, I can only speculate about the actual system, so maybe there's no point for me to suggest features until I can actually try out a first version.