The purpose of this app is to let you make more friends or hook up with strangers. Previously known as Who Near Me, this app can use VOIP to call someone near you. Personally, I find it a bit strange.
Here is something from the description.
WNM Live (formerly known as Who’s Near Me) is a free service that connects you with people near you! Send and receive text and picture messages with nearby people – all without the need to ever reveal your true name, email, or phone number!
People from around the world are logging into the WNM Live network to find new friendships, romance, or just to kill some time by chatting with a stranger in their city – or across the globe. Hundreds of thousands of users have already joined this rapidly growing social network and you are bound to meet people living and working in your city, maybe even someone living right next-door!
It is only for Windows Phone 7 and Windows Mobile. At this moment, the reach should be small. Nevertheless, I think those who uses it must thread it carefully. You never know who is around you.