In the 1990s, the American Physiological Society (APS), like most organizations, was exploring ways to support members and trainees via online resources and programs. Online communication was still primarily accomplished via e-mail, listserves, and websites, although discussion boards and social media were growing in popularity among researchers and educators. Thinking of these interactions as true online "communities" was, in most cases, fodder for computer scientists, editorials, and hopeful projections for the future. As the facility with online communications grew, the demand and need for regular online communication with colleagues became essential. Bulletin boards became discussion forums, social media fostered collaborations and professional networks, and websites became interactive sites to share research ideas, methods, and results. Groups of people who interact regularly began to be called "online communities." Anyone who has ever written or read a customer review at an online store such as Amazon, Macy's, or eBay has participated in a "community of transaction" by seeking information from other consumers to make a decision about buying a product. Seeking information, advice, or simply a connection with others who share a similar life experience (illness, retirement, aging, job hunting, etc.) involves participating in a "community of relationship". Researchers or educators are most likely to seek out "communities of interest" or, more specifically, "communities of practice." For more than a decade, APS has been building the framework for a community of practice for science education and physiology education. This framework, which is described in this article, incorporates teaching resources, professional development, educational research, and network building.