There is much to praise about a recent law passed by California that “requires all web sites, social media sites and apps to allow anyone under 18 to remove content they posted earlier.” Let’s assume the law was different. Let’s assume that there is a broader right to be forgotten. That is, a law is passed that would allow anyone to request that information they submit to social media must be deleted. But what happens if a company refused to comply? Most likely they would raise the First Amendment as a defense, and call this a form of censorship. The information was freely submitted to the company, probably under terms of service that permit the data to be used in many ways, with no promises of deletion. This touches on some issues in my recent essay What Happens if Data is Speech?
Of course, there is also the issue of where California gets the right to regulate internet companies outsider their borders, and maybe those overseas, as SHG notes (perhaps some sort of purposeful availment standard).