Users could be unnerved about the extent to which their conversations are reviewed, at least by computer programs.'We've never wanted to set up an environment where we have employees looking at private communications, so it's really important that we use technology that has a very low false-positive rate,' he said.
In addition, Facebook doesn't probe deeply into what it thinks are pre-existing relationships.
By some measures, Internet-related sex crimes against children have always been rare and are now falling (as are reports of assaults on minors that do not involve the Net).From a business perspective, however, there are powerful reasons not to be so restrictive, starting with teen expectations of more freedom of expression as they age.If they don't find it on one site, they will somewhere else.Under a 1998 law known as COPPA, for the Children's Online Privacy Protection Act, sites directed at those 12 and under must have verified parental consent before collecting data on children.Some sites go much further: Disney's Club Penguin offers a choice of viewing either filtered chat that avoids blacklisted words or chats that contain only words that the company has pre-approved.Yet even though defensive techniques are now available and effective they can be expensive.They can also alienate some of a site's target audience - especially teen users who expect more freedom of expression.'There are companies out there that are doing a very good job, working within the confines of what they have available,' said Brooke Donahue, a supervisory special agent with an FBI team devoted to Internet predators and child pornography.Another pillar in Facebook's strategy is to limit how those under 18 can interact on the site and to make it harder for adults to find them.Minors don't show up in public searches, only friends of friends can send them Facebook messages, and only friends can chat with them.Things like too many 'unrequited' messages, or those that go unresponded to, also factor in, because they correlate with spamming or attempts to groom in quantity, as does analysis of the actual chats of convicted pedophiles.Barring a wave of costly litigation or new laws, it is hard to see the protections getting much tougher, experts said.