Serendipitous Communication

Increased productivity due to one person overhearing another person's conversation and commenting on it. This happens a lot with ExtremeProgramming because people are PairProgramming (thus talking a lot) and are all located in a single room.

Each case of SerendipitousCommunication saves many minutes of work (anywhere from ten minutes to several hours), and can easily happen a dozen times in a day. It adds up quickly.