Isn't it stupid to offer this on a forum where no-one has over 3000 posts?...

Surely you'd rather hit up the "big players" within any given forum, because they're the most respected members and so you're more likely to take notice of their sig.

Take for example, mike.fro above me. He joined this month, yet has more posts then I who joined early in talkfreelance's life. Who would you rather advertise with?

Though if you're simply in it for the search engine rating then I'd advise you to go kick yourself where it hurts... or give me $300 a month for an ad.