Age verification has been the potential online-safety solution of choice for state attorneys general. I know I've written about this plenty, but I have to add something that really struck me in reading all the technology submissions to the Internet Safety Technical Task Force: that the only way any of these technologies would really work for children is if their parents chose to use them. Only bottom-up, not top-down, adoption can really work. In other words, no government can effectively mandate their use because no government can control the global Internet or its global population of users. For example, if a government were somehow to restrict social networking only to adults, its restrictions could only affect social sites based in its country; its teens could simply go to social sites based in another country (there are so many English-language ones outside the US). This was a key factor cited in a recent European Commission report. But back to opt-in parental controls. There are many kinds – from filtering to monitoring to site moderation to ID-verification in specific sites for which parents sign up their kids. All of these can work for children with engaged, informed parents who know what's age-appropriate for each of their kids. They don't work very well for kids who aren't fortunate enough to have that kind of attentive parental support, kids who – for good or bad – find more support online than at home, if they even call it "home." Those are the youth recognized in the research summarized in the Task Force report as most at risk online as well as offline. Those are also the young people for whom age verification could have very negative unintended consequences. It's those possible consequences which have barely begun to be considered and about which my ConnectSafely co-director Larry Magid and I are concerned. We sent a memo about them to our fellow Task Force members (summarized on p. 262 of the full report, which can be downloaded at the site of Harvard Law School's Berkman Center for Internet & Society) and which Larry delineated in his CNET blog.