Via boingboing, a nice but huge pdf file about MMOG, game guilds and distributed cognition written by Constance A. Steinkuehler (University of Wisconsin–Madison). I like her statement about why video game are interesting with regard to cognition.

Despite frequent public dismissals and indictments from the non-gaming community, massively multiplayer videogames (MMOGs) do constitute a complex and nuanced set of multimodal social and communicative practices, tied to particular communities and consequential for membership and identity. As such MMOGaming is participation in a 'Discourse' (Gee, 1999). My research investigates the forms of learning, thinking, and socially interacting that MMOGs recruit from those who play. My dissertation (currently in progress) is an online cognitive ethnography of MMOGs that characterizes the emergent culture of MMOGaming and how participation is constituted through language and practice both within the game (e.g., virtual social interaction & joint activity) and beyond (e.g., the creation of fan fiction & websites). What does it mean to be literate in this social space? How does one become a member of this community? And what import does participation have for the (on- and off-screen) identities of its members? The papers below come out of this body of research.