[beat]

I used to use the term "mob programming" to describe a phenomenon I saw at a shop where I used to work. Officially, the process was Extreme Programming, but the physical layout worked for more. There were two "islands" of workstations with five workstations each - two of the largest monitors we could get those days (24"), room for two seats, and spare chairs. Developers each had small private cubes on the outside walls for email, phone calls, and such. Coding work was done at the islands. In theory, it was "pair programming".

What happened in practice was that any number of programmers might be gathered around a workstation, from a single programmer for a straightforward bit of coding, to a half-dozen gathered around for a thorny problem or a coding/discussion session. It was extremely effective!

[badthingfactory]

I worked on a team that was set up exactly like this. Like you said, it was really effective for some ad-hoc discussion about tricky problems. The knowledge sharing was fantastic and I learned a ton.

The major downside was the chaos. If you were the team expert in some domain, you usually had someone asking questions about that domain every 20 minutes. Sometimes programming takes 4 hours of uninterrupted concentration. That work was very difficult to accomplish.

A small group of us ended up bringing in laptops and separating from the group multiple (sometimes 5) days a week. We found ourselves having to choose between finishing our own work, or helping other people finish their work.