Carfax is a service that provides vehicle history reports to individuals and businesses, aiding in informed decisions regarding used vehicles. It collects and aggregates data from various sources, including state title and registration records, car auctions, repair and service facilities, and insurance companies. By offering insights into a vehicle's history, including previous accidents, mileage, and ownership, Carfax plays a crucial role in the pre-owned vehicle market. While not a data warehousing solution, its extensive database and analytical tools help users ascertain the value and condition of used vehicles, fostering transparency and trust in vehicle transactions.