After noticing a big increase in the abuse of FS/WTB forums, admins will start to enforce these forum rules more closely and penalties of $25k will be given to the appropriate players who can't follow those rules stated.
Hijacking a post or just making remarks in it that shouldn't belong in it fall under abuse of these forums.
Thread owners (being the person that created it) may chatmail an admin to inspect the thread if you think it is being abused
making threads like ***** FS this and that ***** will also be seen as abuse and will still be penalized also.