Twisted is awesome. I used it to write justin.tv's chat server, which is currently running on 18 cpus (3 physical machines) and scales to over 10,000 concurrent connections per cpu. Kyle wrote the video server in Twisted too.
We have a bunch of social features on the web site that need to have very tight integration into the chat server. I just don't see us getting the degree of control we currently have, with an off-the-shelf chat solution.
