its not the amount of posts that matter,but whats in them.
if want proof of this-go on yahoo answers [which isnt a forum,but is very similar in a way] - the yahoo staff on there will reward people with big orange labels under their name that say [top contributor] if have got a lot of understanding in one or more of the sections],and post count does not even come into this.
lots of people think those with big post counts on forums have said a lot of usefulness,and they are never ignored like new members for example can be on some sites,but high post count only says the person is on a lot and posting a lot,not that they are saying something more decent than the user who has just joined but coming up with useful stuff.