Web-based chat, by its nature, is also very distracting. One click and you are reading HN instead of your internal chat room :)
Anyway, when I worked at an all-remote company, we just ran our own IRC server. Then all the channels were work-related. Of course, it was pretty easy to also join other networks, which we did (but would do anyway).
Oy, I dunno. I actually use an IRC gateway for XMPP group chats because irssi does so well for the medium. My team at work uses an IRC channel for adhoc group conversations, and that's the only IRC channel most of us are in. I also have a separate irssi open to freenode, but that's unusual for my team, and the freenode irssi is tucked in a corner where I see it only during interrupts anyway.
OT: I think convore will go the same way, unless the crew can seriously address the SvN problem.