In my couple of inactive months from NB, I visited several forums, all of which seemed to have a "xat.com" chatbox. It's a live chatbox that can be stuck onto any page of a website, I suppose. I've never really hosted a website, so I don't know the specifics, so I wouldn't know about any conditions it needs.
But it's not your old run-in-the-mill chatbox. You can have avatars, post smileys, have admins who can kick/ban people for certain amounts of time, etc.
I'm bringing this up because I can't really run MSN on my computer, which is the main chat client used by NB members, and I think it would be generally beneficial for everyone if NB got such a chatbox.
As far as I can tell, they're free.
And if you're worried that such a chatbox could lag up NB, you could simply have the chatbox at a different address. The chatboxes come with their own URL, so you could put a link to the "Chatbox" up on the Action Bar next to, say, the "Blogs" tab.
Just a suggestion ^^
EDIT: Just got to xat.com to check it out. On the right side of the xat.com homepage is an example of one of their chatboxes.
