This chapter asks whether a large wiki can be considered a Community of Practice (CoP) and whether or not this is a useful question to ask. The focus of the chapter is the Adult Literacy Education Wiki, an on-going creation of adult basic education teachers, administrators and researchers. The ALE Wiki has a core group of very active contributors, over 700 registered users, and more than 720 pages of content. The chapter includes a description of choices the organizers made when constructing the wiki and how those choices create the potential for the ALE Wiki to create a small CoP at its centre. The chapter uses the concept of CoPs as a heuristic to examine the multi-layered participation structure of the wiki. The conclusion is that while the ALE Wiki as a whole cannot be considered a CoP, the concept is a useful way to identify some of the strengths of the wiki and to note the limitations of working with such a large group.