Acknowledgments

We thank Julian Besag, Oliver Downs, Reimar Hofmann, Steffen Lauritzen, Adrian Raftery, Volker Tresp, and the anonymous referees for comments on earlier drafts of this manuscript. We thank David Steinkraus for his implementation of Gibbs sampling for dependency networks. Datasets for this paper were generously provided by Media Metrix, Nielsen Media Research (Nielsen), Microsoft Corporation (MS.COM), and Microsoft Corporation and Steven White (MSNBC).