Platform for Privacy Preferences (P3P) is the most sig-nificant effort currently underway to enable web users to gain control over their private information. P3P pro-vides mechanisms for web site owners to express their privacy policies in a standard format that a user can programmatically check against her privacy preferences to decide whether to release her data to the web site. We discuss architectural alternatives for implementing P3P and present a server-centric implementation that reuses database querying technology, as opposed to the prevailing client-centric implementations based on specialized engines. Not only does the proposed implementation have qualitative advantages, our experiments indicate that it performs significantly better than the sole public-domain client-centric implementation and that the latency introduced by preference matching is small enough for real-world deployments of P3P.