I'm a regular there. Here are my observations.

This is fun. I haven't had this much social fun on-line for a decade. I'm a corporate stooge, and usually sitting at a keyboard and typing for a living is not that social and not that fun for me. As much as I enjoy spending time there, the mere social fun is not the purpose. I've noticed that whenever I join the chat without a clear goal, I tend to drift through pomodoros without achieving that much. I first need to do some GTD-style analysis of what project I want to work on, and what are actionable steps to take during a pomodoro. I like to ask the participants about their projects and I like and find it useful to briefly explain mine.

Apparently a little social salience can go a long way with me. BTW, that is a possibly useful observation for team mangers, and it agrees with what random pop-psychology of human motivation I've heard about.

I'm worried about the long-term prospects of this idea. I think most of the participants are students. During the first summer vacation season we'll likely see a big drop in participation.