There is something fascinating about this: The stadium for a recent U2 concert in Seattle took a picture of the crowd and people can view and zoom into it to tag themselves like it was a Facebook photo.
http://www.u2.com/gigapixelfancam/110604/ There is all this hubub about face recognition software getting good enough to single people out at Football games (etc.) and what sort of privacy implication that has, but here people are doing it themselves. It's kind of neat, but I just don't know what to think about it. Is the next step scanning our ticket stubs with our phones to locate our seat numbers? The phones would upload a map and guide us to our seats, and then auto-tag us in any pictures, maybe with geolocation to back it up. Maybe that's fine?
(No, I was not at this U2 concert. But I did try to go to a Negativland performance in Seattle some years ago only to be surprised to find out the venue held something like 40 people and I was perhaps 60th in line (out of hundreds). What were they thinking? Also I stood next to a model from the Life Drawing sessions where I worked who we had only used a couple times so I didn't know her well, and it was slightly awkward. "You look so different with clothes on," I didn't say.)