Now that the health and medical sector is slowly but surely beginning to embrace Web 2.0 technologies and tactics such as social networking, blogging, and sharing health information, such usage may become an everyday occurrence. This new trend is emerging under the Health 2.0 umbrella where it has important effects on the future of medicine. This chapter introduces some important Health 2.0 concepts and discusses their advantages for health care and medical practice. In addition, this chapter provides a case study for building a Semantic Blog for Gene Annotation and Searching (GAS) among social network users. The GAS Blog enables users to syndicate and aggregate gene case studies via the RSS protocol, annotate gene case studies with the ability to add new tags (folksonomy), and search for/navigate gene case studies among a group or cross-groups based on FOAF, GO, and SCORM metadata. The GAS Blog is built upon an open source toolkit (WordPress) and further programmed via PHP. The GAS Blog is found to be very effective for annotation and navigation when compared with the traditional gene annotation and navigation systems, as well as with traditional search engines such as XPath.