This article investigates collaborative and crowdsourced online writing projects and the economies surrounding them. It describes the conjunctures between collective creativity and contemporary economic regimes and introduces the concept of the promise economy. The article discusses recent literary collaborations that have taken place online between writers who have never met each other in real life and who have never cooperated before. It argues that these cases of collective creation often rest on a specific dialectic between the promises or expectations of these crowdsourced writing initiatives and the failures and disappointments experienced in such projects, which can be seen as participating in a promise economy. “Promise economy” refers to a cultural economy that is based, or dependent, on certain promises that are inscribed in collaborative cultural practices such as cooperative writing, whose dynamics urge participants to create ever-higher expectations for the final product often before the process of creation has even started. This article's analysis of such economies surrounding online creative collaborations and its examination of the dialectics between literary works and the processes behind them contribute to debates on participatory or processual art in the twenty-first century.