Go to someone's profile, and check amount of posts in forum one's most active in, then based on percentage these posts are of total 100% of posts, count all the post amount.
For example, I have 362 posts in general discussion archive, which is 23% of all my posts. This makes me have, totally, about 1573 posts... Wait a second. It sounds a bit too low for me, as far as I remember...
Nevermind, forget it. Maybe they clean the archives or something if topics get too old.
Anyway... I tried Razz