(Get your minds out of the gutter. This isn't in Omni.)

I generally browse FT with multiple windows open: I'll go through a forum index page, opening interesting threads in new windows or tabs, and then read/reply to them as the next index page is loading. I sometimes inadvertently close my last open FT window or tab when I meant to jump somewhere from it. If I re-enter FT quickly enough, its server continues the previous session - that is, the "You last visited" time reflects my real previous visit, not the one I just accidentally cut off.

So, the question: how long do you have to be "gone" before it decides a session is over and really logs you out? If it varies, what's the approximate range?

(Just curious; I can't think of anything useful or malicious one could do with this information.)