This chapter questions the role of reputation in the sharing economy by building upon the analysis of the relationship between the economy, society, and the market offered by sociologist Karl Polanyi in The Great Transformation. Reputation, it is argued here, should be seen as the “fictitious commodity” of the sharing economy. Akin to the role played by labor, land and money in the rise of modern market economy, reputation in the sharing economy represents a non-commodity that behaves as one. First, it is a “symbolic token” that converts use value into exchange value. Second, it is subject to forms of “enclosure” by sharing economy platforms, as the “tokens” that constitute one’s reputation cannot be “spent” elsewhere other than where these are created. This “fictitious commodification” of reputation is argued to be the social precondition for the enactment of efficient “sharing” exchanges.