Since this site is being run on a small private server (as opposed to a large corporate one), my understanding is there will be a limited number of spaces in the Match Maker room due to bandwidth constraints. I believe the current maximum number is either 25 or 50 and can be easily adjusted (current bandwidth usage is being monitored for this purpose). When games are launched, spaces become available. This is also why there is a 5 min timeout period for inactivity. I am guessing if a player does nothing in the lobby long enough, and there is a waiting list to get in, when they time out, they move to the back of the queue and the person at the front is allowed to enter.
Currently, Mark is working on getting the new tour set up and running ASAP. Since the Match Maker lobby appears to be functional, any further embellishments will probably be on the back burner until this is accomplished. It's gonna be good!