90,000 members is a helluva lot of members...but how many of those members do you think are active? I usually see 700-800 or so people online when I stop in which is a far cry from the 90,000 that are registered.
Also, how many lurkers do you think there are? If there's 700 online, do you there there's twice that many lurking? Half that many?
Kinda brings up a lot of questions.