The availability of medical and health information on the world wide web has led to a long discussion about the reliability of that information. Various medical, political, and independent organizations have created user-friendly tools for finding reliable medical/health information on the web and have been faced with the challenge of (re)defining what it means for information to be reliable. Little attention has been given to the work of reviewing web-based information and applying selection criteria to individual sites. In this article, the authors examine how guidelines are applied in practice and discuss how the selection criteria and the practices of applying them reinforce distinctions (such as those between lay and expert, global and local, nonprofit and commercial, etc.) that current medical sociology and informatics literature suggests have been broken down by internet technologies and the availability of web-based medical information.