It's not about how much you post but what you post. Most forums i'm on don't even have a post counter visible.
Post counts mean diddly to me.. however, if people turn off the displaying of the counter... it just makes it feel like something is missing to me.
Well they generally are an indicator of the time a member has been around on a board (not counting spamming), which helps identify the head honchos (like the guy on SegaXtreme with more than 8 million posts :smt043 )
I dont think you can always use post count as a good example. See my profile number? I joined the new forum within a half hour of its opening. I have been here longer than yakumo (by 40 minutes or so) but he is a mod. Where is the justice? :smt043
And here I sit at a lowly 279... Edit: Oh yeah, this doesn't include my old board number...I had like 200 or so there...boohoo