With FourSquare's continued rise in popularity, I have noticed a definite challenge with the service in popular areas, namely... WHICH place name do you use to check-in?
For example, here I am at the Philadelphia International Airport and a quick search on "PHL" in FourSquare gives you 25+ results... with even more that don't use PHL in the text. As the image shows, there are many different levels of granularity, too, with locations being created for specific gates and even for specific seats on flights.
Where do you check-in?
Part of the issue is that in many ways you are incented to create new locations. You get extra points for adding a new location... and may have an easier job of becoming "mayor" of a new place if that is important to you.
There are also times when it is simply easier to add a new place than to wait for FourSquare's servers to "locate" you.
It all adds up to a lot of "places" and some resulting confusion over which place to use when checking in. As FourSquare matures the folks there may need to do some curation and pruning and merging of places. Or perhaps start showing results ranked by number of checkins... or votes... or something like that.
Right now, as it starts up, the "Wild West" approach (anything goes) makes a lot of sense... but as more folks use FourSquare, it may make sense to provide a bit more guidance in terms of which place name people should use when checking in.