Chapter 5 discusses the dynamics of supply and the way it impacts on protest participation. Supply refers to the mobilizing context and the opportunities staged by organizers to protest. It relates to characteristics of the movement, and the contemporary more fluid and virtual networks of networks. We will discuss how the issues the actions are aiming at and the various forms they might take impact on their appeal to potential participants. Next, we will introduce the concept of multi-organizational fiels (MOF) and discuss what role embeddedness in MOFs plays in types of civic engagement. We will close the chapter with a discussion of the mechanisms at work in the supply side of protest. We will argue that linked to embeddedness are patterns of identification which make people more or less susceptible to the appeals of one social movement organization over another.