Apparently, by fingerprinting young girls to prove they are who they say they are:
Anne's Diary is the first biometrically-secured social networking site for children in the world. The site offers girls in grades 1 to 8 (ages 6 to 14) a secure environment in which to keep a private diary and communicate with their peers around the world. Members can also enter contests, play games, participate in book clubs and receive homework help.
What do you think of that?