People don’t think about privacy issues because our psychology doesn’t trigger much emotion for autonomous opt-in broadcast to people not currently visible. There’s no sense of violation. It’s very easy to forget about it and it starts to feel normal. In a way it’s also empowering to be so open; it makes you feel like you’re not afraid of anything.

If you actually step through what is happening when you use these apps (all the individual people you are informing of where you are and have been, your habits, preferences—a complete digital record) you might start to see some risks. Then ask yourself, even if it was easy, would you go round handing out that data on paper to large groups of contacts indiscriminately on a regular basis indefinitely? That’s what’s actually happening here. Now remember there are people (trolls) who get a kick out of being able to do things to do from a safe distance for no reason at all. There are also people closer to you who have fragile egos or maybe you were just in the wrong place at the wrong time. Using something like Foursquare is giving these people ammunition. The fantasy we like to believe is that everyone we know is trustworthy. The reality is not so rosy.