Our team is growing, but we're also growing specialized. We've already been using ticketing/bug tracking/case management software for years--as well as IM clients informally--but as another engineer and I were discussing, it'd be nice to have an IRC-like communication system. Basically, it'd be nice to have logs of discussions, as well as both long-lived and ephemeral groups/channels (the issue that precipitated this was a discussion that was happening on IM, while someone external to the conversation changed the state of a system we were working on).
At the same time, we all tend to spend a whole bunch of time with Visual Studio spanning our [one] monitor, so it'd be nice to integrate with screen real estate already being used. That, and it'd increase user buy-in by being able to point at an extant add-in and say, "Here. This is what we want to do, and this too makes it real easy." IRC would be great, but thinking about it, there's nothing inherently wrong with XMPP, either.
Are there any add-ins like this that people are using? I did find one that's four years old, and doesn't exactly have the biggest user base.
As a minor aside, the idea was also sparked by Ted Dziuba's most recent article, which shows XEmacs playing nice with an IRC client.