"A service like foursquare can be useful to different people in different ways."

Which indicates that their focus is too broad to capture a critical mass of users that use it in the same way. I don't think a pivot is necessary, just a focus. They probably have enough $ to figure it out, but IMHO they need to find something soon and stick with it. I suppose "Radar" is supposed to be it, but I don't see it.