The first generation of search tools provided remarkable capabilities to many researchers for finding specific information, navigating to desired websites or tracking down needed documents. A second generation of tools is helping researchers conduct exploratory search in situations where the goals are less clear, where complete coverage is necessary, and where proof of absence is required (patents, legal precedents, etc.). However, the third generation of tools turns search into social discovery, in which colleagues, informal groups, companies, non-profit organizations, professional societies, and international federations are motivated to find, filter, organize, annotate and summarize voluminous information resources. The Reader-to-Leader framework describes the usability and sociability design features needed to motivate readers, contributors, collaborators and leaders. The Social Discovery framework, proposed in this paper, suggests that effective design enables people to engage in dialogs over weeks and months to create capacity (in the manner described by the Reader-to-Leader framework), and become more effective solution seekers. Much work remains to be done to validate these social discovery frameworks and refine them to fit diverse contexts.