This is why privacy is such a Hard problem: damn near everything you do leaks information. If I post anonymously somewhere, my choice of words would narrow down

This is why privacy is such a Hard problem: damn near everything you do leaks information. If I post anonymously somewhere, my choice of words would narrow down who I am. If I mention that I live in San Francisco, that immediately excludes all the people who live somewhere else and aren't lying. As I browse through web sites, I leave a trail across a bunch of sites' access logs that could all be pieced together and linked to my IP address. (I've got my browser set to block those social tracking buttons, but still information leaks out.) The same thing applies to the physical world (e.g. every printer has its own distinguishing quirks if you inspect the printed output); the only difference is that the internet makes it a lot easier to snoop on people in bulk.