As society becomes increasingly globalized and networked, online participatory cultures provide youth with experiences to foster dispositions and skills required to engage in virtual spaces. This 5-year longitudinal case study explores the role of affect in the composition practices of an adolescent girl in Scratch, an online programming community. The author applies affect theory to examine why a successful member in a participatory culture would suddenly leave the space where she found success. Findings from this study inform understanding of the role of affect in participatory cultures, including a perceived need to perform. The author provides considerations for literacy educators to foster skills and dispositions necessary for students to engage in sustainable literacy practices in participatory cultures.