This document discusses techniques for reducing fraudulent online transactions. It presents research on how telling buyers their personal information is known, such as IP address or location, can increase honest behavior. Adding a message that the seller knows this information about the buyer increased honest transactions from 80% to 89% in one experiment. However, location data may not always be accurate and more work is needed to determine how often the location is close enough to be effective. While addressing small-scale or "hobby" fraud, professional fraudsters require different approaches. Psychological methods show promise but need further understanding of human behavior.