I would guess that active members would be members who would be posting messages or that are logged on at the present time. I don't know what is used to calculate the amount of "Active Members" at the bottom of the page but it doesn't work to my thinking. Presently it says Active Members 6,489. Now I have a question, How can you have 6489 active members when only 4982 members have ever posted a message on the forum??