Foursquare is the most popular location service app on the planet. I have been using it for a couple years now and very active. I use it for a variety of reasons, one being letting my friends and clients know of cool and interesting places to visit.
So you are getting used to checking in everywhere and you are burning up the data limit on your iPhone and you could just become the next social butterfly but hey, you made it to 25 check-ins. Way to go!
The unlock text reads:
You’ve checked into 25 different venues! Got any great recommendations (like the best time to visit or a secret menu item)? Share them with the world! Add Tips to places you love and get suggestions from others.