[cinq]

1) Adding a search feature that is on the ads section that will only throw up ads is more efficient for the end user, don't you think ?
2) Adding to a member's post count can be easily done with a single query, from anywhere outside the forums.
3) Yep, but what if the seperate ads section also has its own trader rating system.

Well, I just have a personal preference to keep most things out of forum threads/post, you could always do a classifieds adverts hack such that adverts are posts in the forums too of course