A knife is useful for different people in very different ways, but it's a very, very focused tool (unlike a spork). foursquare is a very focused service. The fa

A knife is useful for different people in very different ways, but it's a very, very focused tool (unlike a spork). foursquare is a very focused service. The fact that users find different usages for it without them having to release tons of unfocused features only proves it's well designed