Certain types of information are considered “public record” under the law, which means that anyone has the right to access them. That also means that anyone has the right to post those records, i.e., post personal information.
Public record sources include legal documents, voter registrations, and mortgages. Public records laws were created before the Internet, when documents were physical copies. Now these records are far more accessible and visible than they’ve ever been, and our outdated laws do not treat them differently than if they were physical copies.