Twitter is free (iPhone, iPad). Read about what you care about: instant messages from your friends, experts, favorite celebrities, and the latest news from around the world.
Find my friends
Find My Friends – Free (iPhone, iPad). The Apple-style social networking app Find My Friends lets you quickly locate your friends and family using your iPhone, iPad, or iPod touch.
Foursquare
The foursquare platform gives you an opportunity to learn a lot about the city you are in, and even to arrange a spontaneous meeting with your friends.
