and most other social networks ban children under the age of 13. But Facebook has no way to check the actual ages of users.

Consumer Reports determined about a year ago that , and some 5 million of those were under the age of 10. Surely those numbers are higher now.

That means millions of second-, third- and fourth-graders are on Facebook, and potentially subject to the social pressures, potential bullying and other problems that kids usually don't have to deal with until they reach middle school or high school.

Social networks are also the single most convenient service for anyone who wants to prey on or exploit children. It's easy for anyone to set up an account under a pseudonym and pretend to be any age or either gender. Then they can simply search for first names and collect the profiles of users who look very young. If they send friend requests en masse, some percentage of children will inevitably accept. Then the predatory social engineering can begin.

Another fear parents have is that their children will be exposed to extreme violence, pornography or criminal behavior.