Not exactly the same, but you may find a product I worked on a few years back, www.kona.com, to be of academic interest as someone who is looking at different c

Not exactly the same, but you may find a product I worked on a few years back, www.kona.com, to be of academic interest as someone who is looking at different communication methods. We used a similar "topic" method and allowed users to fork conversations to have the best of both worlds -- linear chat for most cases and topical chat when a breakout was needed.