They will start changing the definition of porn to the point you will need to prove your age to view info about contraceptives, breast cancer, etc. They will also theorize people should be required to prove they're 21 in order to visit beer making or wine making sites, sites retailing alcohol (where online liquor sales are legal), and other sites. Will people be required to submit a photo of their drivers license in order to register on these sites? Even if info is required to be destroyed after registration, this info could be stolen during the registration process. In states allowing mail in voting they will probably add voter ID laws knowing many potential voters won't feel comfortable sending info to prove they are 18 and elegible to vote.