Keeping track of your friends is really not such a difficult task any more, thanks to the advent of Websites like Foursquare & other Social Sites. Now, there's an iPhone App called Highlight that silently tracks your friends & pinpoints their position vis-a-vis you.
Eg: If a friend is in a coach behind you in your subway train, Highlight will beep you his/her location, letting you meet up with that person.
In addition to that friend's profile, you can also see his name, photo, mutual friends, & almost everything about what that friend has chosen to publicly share. It also helps you remember that friend's or contact's name, in case you have forgotten it.
The guys at Highlight say the App runs quietly in the background, depending on the GPS. The minute it locates a friend, it will let you know. Uncanny? It's like having your 6th sense go into overdrive.
Highlight uses Facebook as the login system.
Highlight is Free to use & is compatible with iPhone 3G, iPhone 3GS, iPhone 4, iPhone 4S, iPad Wi-Fi + 3G & iPad 2 Wi-Fi + 3G & requires iOS 4.2 or later version.
You may click here to download Highlight on your iPhone