This study explores frequency of election-related chatter as an antecedent to agenda setting. It conducted a longitudinal analysis of 38 million tweets from the 2012 election. Users who participate more in election talk align more with partisan media than less active users. Users who participate less align less with partisan media and more with mainstream media. Overall, agenda-setting relationships differ by participation in election-related talk, with more active users exhibiting a greater agenda-setting effect across all media types. This study provides evidence that as Twitter users talk more about the election, they appear to do so in more homophilous information environments. These environments can alter their perceived importance of issues to match more partisan media. This study echoes previous research that has shown large conversations on Twitter to be more akin to partisan information.