This article explores the development of teacher identity in the 21st century. The simple way to describe this discussion of identity is that it is complex. In an attempt to unpack this complexity, this article begins with a discussion of definitions of teacher identity; then links that discussion to the literature on how 21st-century web 2.0 tools, the dynamic digital venues that encourage the social construction and consumption of texts through virtual interactions, situates identity; and concludes with a look inside a study of preservice teachers' work with these tools as a vehicle for their own Identities-in-Practice. (Contains 8 figures.)