This is the kind of service that will have Social Web introverts shaking all over. Shooting Star is an application that can take care of automatically tagging people on photographs. This is accomplished by using advanced image recognition techniques that can tell who is who (and what is what, of course)
People either love being tagged in images all over sites like Facebook, or they opt out of that completely. Some are tagged in the most ridicule photographs you could imagine, photographs where they are hardly visible, and they couldn?t love it more. 
