We conducted two experiments to explore how moderation, response rate, and message interactivity affected people’s intent to participate in a web-based online community. In our first experiment, 62 participants observed either a moderated or an unmoderated online community and answered questions about their intent to participate in the community. The participants who viewed the moderated community reported significantly higher intent to participate than participants who viewed the unmoderated community. In our second experiment, 59 participants observed a different online community in which we manipulated both the rate (in time) of posted comments and the interactivity of each comment. We derived our manipulation of interactivity from Rafaeli’s (1988) definition of interactivity as message contingency. Participants reported significantly greater intent to participate in an online community featuring interactive messages, but only when response rate was slow. These results indicate that both structural features of interfaces and content features of interactions affect people’s intent to participate in online communities.