The article discusses the concept of "Medicine 2.0," which refers to the application of Web 2.0 technologies and approaches in healthcare. It highlights the integration of social networking, participation, apomediation, collaboration, and openness in health care, patient engagement, and biomedical research. The Journal of Medical Internet Research (JMIR) is publishing a theme issue and hosting a conference on Medicine 2.0 to stimulate research in these areas. Web 2.0 technologies have significantly transformed the design, appearance, and functionality of web applications, changing user expectations for open and interoperable systems. The emergence of Personal Health Application (PHA) platforms, such as Google Health, Microsoft HealthVault, and Dossia, has enabled patients to control and share their health data. These platforms represent a "disruptive innovation" that shifts the focus from health care providers as the sole custodians of medical data to patients who can grant permission for their data to be used by various entities. The article also discusses the broader concept of Medicine 2.0, which includes the idea of moving away from hospital-based medicine to promote health, provide care in people's homes, and empower consumers. It emphasizes the importance of collaboration, participation, apomediation, and openness in the new health system. Social networking is central to Medicine 2.0, enabling users to connect, share information, and collaborate. Participation is another key theme, with PHR 2.0 allowing patients to share parts of their electronic health records with others. Apomediation refers to the use of networked collaborative filtering processes to guide users to credible information without intermediaries. Collaboration involves connecting diverse groups of people, including researchers and the public, to improve knowledge translation and research application. Openness is also a key theme, with Web 2.0 promoting transparency, interoperability, and open source principles. The article concludes that Medicine 2.0 represents a new, better health system that emphasizes collaboration, participation, apomediation, and openness, moving away from traditional, hierarchical structures in healthcare. The Journal of Medical Internet Research is supporting the Medicine 2.0 congress and theme issue to foster research in these areas.The article discusses the concept of "Medicine 2.0," which refers to the application of Web 2.0 technologies and approaches in healthcare. It highlights the integration of social networking, participation, apomediation, collaboration, and openness in health care, patient engagement, and biomedical research. The Journal of Medical Internet Research (JMIR) is publishing a theme issue and hosting a conference on Medicine 2.0 to stimulate research in these areas. Web 2.0 technologies have significantly transformed the design, appearance, and functionality of web applications, changing user expectations for open and interoperable systems. The emergence of Personal Health Application (PHA) platforms, such as Google Health, Microsoft HealthVault, and Dossia, has enabled patients to control and share their health data. These platforms represent a "disruptive innovation" that shifts the focus from health care providers as the sole custodians of medical data to patients who can grant permission for their data to be used by various entities. The article also discusses the broader concept of Medicine 2.0, which includes the idea of moving away from hospital-based medicine to promote health, provide care in people's homes, and empower consumers. It emphasizes the importance of collaboration, participation, apomediation, and openness in the new health system. Social networking is central to Medicine 2.0, enabling users to connect, share information, and collaborate. Participation is another key theme, with PHR 2.0 allowing patients to share parts of their electronic health records with others. Apomediation refers to the use of networked collaborative filtering processes to guide users to credible information without intermediaries. Collaboration involves connecting diverse groups of people, including researchers and the public, to improve knowledge translation and research application. Openness is also a key theme, with Web 2.0 promoting transparency, interoperability, and open source principles. The article concludes that Medicine 2.0 represents a new, better health system that emphasizes collaboration, participation, apomediation, and openness, moving away from traditional, hierarchical structures in healthcare. The Journal of Medical Internet Research is supporting the Medicine 2.0 congress and theme issue to foster research in these areas.