I know some of you went to presentation that Jabari Mahiri gave last year on digital literacy instruction and a point he made during his talk was that people -- teens included -- who are actively participating in on-line communities as part of their daily routines (e.g., Second Life) see themselves as having on-line identities that are not only equally "real" as IRL but that this next generation of technology users and consumers are developing and establishing a sense of identify which is much more dynamic/fluid.... Mahiri said a great deal more on this topic (and more coherently than I am trying to restate here) but I think there is a link here between what Mahiri was saying and what Lankshear and Knobel have suggested.
Of course, at this moment, I have neither my Lankshear and Knobel book or my file with my notes from Mahiri's lecture. I will try and gather those soon and take another stab at explaining my point soon. But I didn't want to forget about this in the hectic pace of finals, Thanksgiving, etc.