On online selling sites, such as eBay, eBay alternatives and classified ad Web sites, 0FB is an abbreviation used to mean zero feedback. It is in reference to a new member on the site who has not completed any buying or selling transaction on the site. Some online shoppers will not purchase items on an auction site form a seller with zero feedback. Some sites will allow sellers to make purchases and complete feedback transactions to improve overall score.
Recommended Reading: Online Auction Abbreviations