WHEN it comes to protecting children on the Internet and keeping them safe from predators, law enforcement officials have vocally advocated one approach in particular. They want popular sites, like the social network MySpace, to confirm the identities and ages of minors and then allow the young Web surfers to talk only with other children, or with adults approved by parents.
But performing so-called age verification for children is fraught with challenges. The kinds of publicly available data that Web companies use to confirm the identities of adults, like their credit card or Social Security numbers, are either not available for minors or are restricted by federal privacy laws.
Nevertheless, over the last year, at least two dozen companies have sprung up with systems they claim will solve the problem. Surprisingly, their work is proving controversial and even downright unpopular among the very people who spend their days worrying about the well-being of children on the Web.