One odd detail that I think was vital to how the group functioned was a result of the first Unix being run on a clunky minicomputer with terminals in the machine room. People working on the system congregated in the room - to use the computer, you pretty much had to be there. (This idea didn't seem odd back then; it was a natural evolution of the old hour-at-a-time way of booking machines like the IBM 7090.) The folks liked working that way, so when the machine was moved to a different room from the terminals, even when it was possible to connect from your private office, there was still a "Unix room" with a bunch of terminals where people would congregate, code, design, and just hang out. (The coffee machine was there too.)

Rob Pike (2004) in interview at slashdot.com, Oct 18 2004