They have (had?) uniqueIds. But they don't solve the problem of identifying real users. You can simple fake them or take a real one from somewhere. Information-

They have (had?) uniqueIds. But they don't solve the problem of identifying real users. You can simple fake them or take a real one from somewhere. Information-Density of a single value is far to thin to be a reliable indication on whether someone is a real human or just a script.