For more than 20 years, states have been keeping public lists of convicted sex offenders. These registries are intended to help police and communities monitor the whereabouts of nearly 800,000 pedophiles and others found guilty of sexual crimes. Many people are listed for crimes committed when they were minors and not all are egregious: Sending a lewd text or public urination, for instance, can lead to sex offense charges. We look at sex offense registries, the restrictions for those on the lists and the protections these restrictions can offer communities.