Organizing vision theory is an institutional alternative to the economic-rationality view of IT innovation diffusion. Institutional theorists have called for more attention to cognitive processes and structures in order to understand institutional mechanisms. Our objective was to unpack the cognitive structure of an organizing vision to understand its role in the diffusion of IT innovations. We focus on the know-why component of organizing visions and on social media as an IT innovation. In a two-stage study, Stage I leveraged schema theory, the "orders of worth" framework’s six justificatory principles, and relational class analysis to discover the hierarchical structure of the social media organizing vision. This resulted in a view of the organizing vision as comprised of four schemas, which we conceptualized as visions-in-use, and ten nested business use cases, each comprised of different combinations of the six principles. Based on this understanding, Stage II explored how community appropriations of visions-in-use and business use cases from the repertoire provided by an organizing vision shape four facets of an organizing vision—coherence, continuity, clarity, and diversity—and how these facets influence diffusion of the IT innovation. We found that the two vision facets we surfaced— clarity and diversity—are essential to understanding diffusion and how and why coherence and continuity matter to diffusion. Much as the "vision" of a musical jam session emerges from players’ multivocal performances, an organizing vision emerges from community members’ multivocal discourse about an IT innovation. Just as a jam session depends on a structure of rules and individual player creativity, diffusion of an IT innovation depends on an organizing vision that offers prospective adopters a well-defined repertoire of moves to choose from, yet affords them the freedom to improvise.