Total number of posts?

A comment in UncleBeer’s A large number thread got me wondering… On the page listing the fora, there’s a number listed for total number of posts-- I won’t bother mentioning it here because by the time anyone reads this it’ll be out-of-date. The funny part is, though, if you add up the listed numbers for all of the fora, you get a result that’s about 10% less. Which is correct, and why the discrepancy? I suppose that things like moved, closed, and archived threads, or deleted posts, might cause some weirdness, but I find it hard to believe that such situations would account for one post in ten. So, what’s the straight dope?

There were some threads archived on the UBB board that are to this date unavailable in vB. I suspect they are included in the grand total, but not in the forum totals.