What is Wiki-Buy?
It is possibly the first User Built Shopping Site! Anyone can list items that they want to sell, and post reviews of items or sellers. You can post a listing for an item you are selling on Amazon or Ebay or a similer site with an url, or just post a listing for something you are selling privatly, with your email or home address.
To see a sample product page, click here.
To see a sample user discussion page, click here.