We keep track of usage for Halsoft rooms and user-created rooms (that are in the
User Created Rooms list) all day long, and show the Top 100 in the web page.
Other rooms can show up in the list if they are frequently used, but they drop
out of the list if they don't maintain high usage. The list clean-up happens
periodically. You need 4 or more people to consistently stay in a room to keep it in the list.
The rooms that stay in the list with low usage are ones that are listed in
User Created Rooms.