I think location services like FourSquare are helpful when trying to find friends and such, but I don’t use them very much in real-time. I am more likely to comment on a place where they have been rather than say, “I’m on my way”. That is partially due to the lack of adoption of these services by my friends. I will usually plan something out with friends and family rather than rely on a spur of the moment decision and a scramble for FourSquare statuses. For someone with a large network that is using these services, I can see there being more of an opportunity for those scenarios. Especially if you are traveling with a large group that may be spread out (conventions).