Here’s an interesting piece on privacy and geolocation services. Some excerpts: “When it comes to geo-privacy there are two extremes. Foursquare makes you explicitly check into each place where you want to share your location. … On the other end of the spectrum is Google Latitude, which constantly broadcasts your location everywhere you go, but only to people you allow to see it and only at the level of detail you are comfortable with. … Somewhere in between the concept of the explicit check-in and constant geo-tracking is the notion of geo-fences. The idea is that you would basically draw fences around neighborhoods or other locations from where you want to broadcast where you are and places where you don’t.” Via Glenn.