Expect Us focuses on four online communities: Anonymous (4chan.org), The Pirate Bay, World of Warcraft, and the IGN.com posting boards. In all of these online communities, members engaged deeply with political issues in a range of ways. However, only two of the communities mobilized politically. If political behavior occurred on all four communities, why did only two of these sites foster political mobilization among their participants, while the other two did not? Using ethnographic methods, Expect Us argues that key structural features about the birthplaces of the four communities shaped the type of political behavior that emerged from each. The book argues that the likelihood of political mobilization rises when a site provides high levels of anonymity, low levels of formal regulation, and minimal access to small-group interaction. Once these factors are present, the nature of the communities themselves—their values and emergent norms of behavior—then appears to influence whether there is a conflict between the dominant community norms and offline legal and behavioral norms. Although this normative conflict is by no means a perfect “recipe” for predicting political mobilization, it certainly appeared to set the stage for cohesive political action by an online community.