http://twitter.com/CarfaxReports - Carfax is a vehicle history report service that helps people purchase a second-hand vehicle. The information used by Carfax is collected from various sectors in the automotive industry and compiled to help buyers decide which used car to purchase. Carfax.com has samples of how a vehicle history report looks like. The information you get from a Carfax report can help you make a decision when it comes to investing in used cars.