Karpf conducts research on the Internet and political organizing. He studies how the new media environment affects organized political advocacy and, in particular, how the new generation of “netroots” advocacy groups (MoveOn.org, Progressive Change Campaign Committee) differs from the older generation of “legacy” organizations (the American Civil Liberties Union, Amnesty International). He has published on the topics of “clicktivism,” online fundraising, the Internet and electoral campaigns, and the political blogosphere. He regularly blogs about these topics at ShoutingLoudly.com. Prior to entering academia, Karpf was a longtime volunteer leader in the Sierra Club. He served as National Director of the Sierra Student Coalition in 1999-2000, Sierra Club Vice President for Training in 2003, and was an elected member of the Sierra Club Board of Directors from 2004-2010.