Thanks to iOS 5, Foursquare has a new Radar feature in its iPhone app that's insanely cool. Radar will smartly let you know if you're near friends, around a place on your To-Do List or followed and will even notify you when the app is closed. It's like a super useful Find My Friends.
Foursquare's examples are, "If you follow a list, like the 101 Best Dishes of 2011, foursquare will let you know when you're next to one. Or you save that yoga studio to your To-Do List (because you really want to try it); we can remind you when you're close."
It just works! Radar finds the places you've already wanted to go but didn't know were next to you. So smart I might start using Foursquare. The new update of Foursquare should be hitting the App Store soon. [Foursquare]