Only down side, is that people could end up posting 50 worthless and spam laden posts, just to get those 50 posts, and then try to sell... Perhaps a time restriction, rather then post count would have more of the desired effect. AKA, had to have been a member for a couple months at least.
This way, even if they do spam (and yes it's possible to get 50 posts in 1 day; just look at what we were doing in the GF7800gts thread
), it wouldn't help them a bit...
If you ask me though; this isn't so much what bothers me; as those who join for no other purpose then to spamvertize their website, or start posting random commercials. "Aquarian age boy", along with use4d were among some other rather annoying peddlers of things that weren't even computer related to begin with