This whitepaper argues that ad servers should not be viewed as a commodity and that several factors are important when choosing an ad server. It summarizes these factors as: 1) the basics of ad serving and data collection, 2) multichannel capabilities and user-level data correlation, 3) platform integration, 4) customization, 5) independence, 6) corporate commitment to ongoing investment, 7) company stability, and 8) a track record of success and experienced people. Choosing the right ad server is important because it is the central conduit of user data and critical to a modern data-driven marketing approach.