How does the thing at the bottom work?

[MentatTux]

How does the thing at the bottom, which says how many users are active, work? Which PHP functions does it use? Or does it store who's logged in in a db? If the latter, then how does it know when someone leaves? I would get the source, but I'm at school at the moment and REALLY bored :)

[Vinay]

i havent seen the source.. so i'm guessing:

it puts it in a running db with timestamps, and people "leaving" is probably detected by inactivity for a certain period

now, i dont have the source on me either :p

[brentj5]

COOKIES!