For example, when I lived in NYC I used to enjoy the game aspect and knowing where my friends were. When I moved to Tokyo, these weren't that useful to me. Now I still heavily use the application because I find their venue locations to be more accurate than google maps.
Beware of people predicting doom because it doesn't solve their pet-problem. I can't tell you how many friends I have that initially signed up with twitter, posted 5 or 10 tweets and then went dark for months or years only to become active again. Twitter failed to solve a problem for those users initially. What held twitter through (besides tons of investment money) is a core user group that loved the service as it is today. Foursquare has that.