The weblog format has increasingly been adopted by academics in recent years, both as a teaching tool and to disseminate and discuss their own research interests. Academics are turning to blogs to exchange ideas about their discipline, their wider field, the academy, and beyond. Doing so, however, raises questions about personal identity with implications for life beyond the blog. Academics, because of the public nature of weblogs, the self-reflection encouraged by the form, and their analytical frame of mind, serve as useful case studies in exploring these questions. This article explores what it means to have an online identity in the light both of works by two commentators on identity in the postmodern world, Madan Sarup and Walter Truett Anderson, and of the author's own experience of blogging over the past five years. Weblogs, while they afford opportunities for identity construction and reconfiguration, can end up changing their authors' sense of identity in ways they may not expect.