How about this. A flag for advertisements that automatically sets a link to the Product Showcase forum, and closes the thread. So a merchant has a thread title, example, 'Mike3 wellington boots!', checks the advertisement flag, which results in a closed thread with a link (and a preview pic if they want to upload one) to the showcase forum. That way if people are interested in that item they have to go to the showcase forum to view the details. That way you could also set in your preferences whether to see adverts just like nudity and/or violence.