I used Prosody (XMPP Server), with a custom module. The whole site is built around XMPP multi-user chat. Front-end is primarily Backbone/Strophe(xmpp library)/Jquery.
1-5) Yea, lot of little stuff I'm gonna need to handle.
6) Since there can be many people in the room, skipping, rearranging, repeating, looping, all of these things are going to have to be voted on.
Lastly, I think it may well be a failure on my part, but the title bar # indicates messages received while you are tabbed away from the window. I detected this by checking to see if the chat input box was in focus (from my understanding that's how gtalk does it). It's clunky, and I should probably figure out a better way to do this.
Thank you for your feedback :)
Also, I've made the Javascript code available on my github (Since I need to find a job):
https://github.com/ahaque/lh
Yea, there's a lot of little stuff I have to iron out. I really wanted to get some kind of working version up, but there are a lot of nitty gritty stuff that needs to be ironed out.
Oh definitely, I guess I just wanted to say something about it's current state. Come see my site, its finished, but not really (not the most captivating title ;p).
Thx for the feedback, a lot of the stuff you mentioned are definite problems. Many people have mentioned not really being sure on what to do on the site. As for the syncing, everything is synced within reason (the app accounts for a 10 second buffer delay, in which case it resyncs, otherwise it tolerates the delay).