You must follow strict rules listed in the stickie at the top of the forums. Puppies must be at least 10 weeks old before listing, you must include all 14 line items as outlined in the stickie and there are strict rules about bumping your thread, how many you can have per week, and how many posts you can make in the "for sale" forum per week.
Unethical behavior can also get a seller banned from the "for sale" forum. This post:
http://www.yorkietalk.com/forums/gen...ouseranch.html Indicates there might be a problem along those lines.