As far as I know, you can't, though I'll admit I haven't bothered trying to find out if there is a way. Would it matter if my post count was 500 posts more or less?
edit :
Unless you of course post only in forums that add to post count. Then you can look at your post cound under your avatar, but .. I think it's fairly unlikely that someone would only post in those forums if they've been here for a while.
