Participants in online transactions have little or no information besides the username of the business partner. Hence the importance of a method for quantifying user trust. The platform's user reputation system is, in effect, a trust ranking system. By allowing, after the completion of a transaction, involved parties to rate one another, the system creates a reputation score. The reputation (negative or positive) improves or reduces a user's chances to acquire or sell items. The system is a safeguard against fraud, and, in time, eliminates from the community those with a negative reputation.