As tagging photos becomes easier and more common, the most immediate effect is a cultural shift in what is private and what isn't. Kapadia said things we may be willing to share in small groups are now often shared with large groups via social networks. And the anonymity individuals once expected in crowds has been eroded.
"The way things are headed, it's going to be easier for people to tag you in photos, so you're going to be less and less anonymous in some ways when you're walking down the street or going to a party," Kapadia said.
Cameron Scott covers search, web services and privacy for The IDG News Service. Follow Cameron on Twitter at CScott_IDG.