This document outlines key concepts around participation and knowledge from a situated perspective. It discusses how participation in a community involves the purposes, norms and challenges of the moment's activity, the tools used including technology and languages, and the community's history, assumptions and relationships. Through interaction and joint action, knowledge is constructed but is not absolute or fixed, and depends on what is relevant, meaningful and useful for the community. Knowledge is not portable or static, but is transformed and reinvented as it spreads between communities. Educators should consider what constitutes meaningful participation in a given community and how issues of gender, power, race and class influence whose knowledge is prioritized.