My credit card website times you out after a certain amount of inactivity and you have to log back in. For SMF, I can't understand any reason for doing so.
Likely the same way it does it.
The way the
Last Activity page works is that it lists the last users logged in, the last page they loaded and how long ago that was. Within 15 minutes of you loading that page. Anyone wanna bet it has something to do with that?
(It adds your time between page loads to your total time logged in, and if you don't load a page after 15 minutes it adds 15 minutes and kills your session.)
Were we still really wondering how it works? Maybe I just jumped to conclusions.
Basically anyone that wanted to cheat that number could load Opera and have it refresh once every 15 minutes. Any faster than that and you're just wasting iago's precious bandwidth.