Active members calculation

[jjanmarine3]

How is the 'active members' figure at the bottom of the forum calculated, I have noticed that this figure has dropped from +- 2995 a few weeks ago to the current 2934.
and...does logging in and out affect this figure at all ?

 

[cheechako]

vBulletin counts active users as those who have logged in within a certain time frame. The board admins set that time frame in the options for the forum.