Of course, most of what the government “knows” about you is “known” only in the sense that someone could get at it if they wanted to find out more about you – or if your data matched some pattern that they were investigating. So, in a sense, the data that the government collects are harmless – that is, until such information is used for a real-world purpose, such as putting people on a no-fly list or forcing into an institution someone whose online posts are “troubling.”