In the next few years, device-to-device sharing of music, videos, and photos will become commonplace. That's thanks to a new crop of proximity-based apps—including Color, Bump, and Mover—that provide a simple way to share media between phones. One of the most interesting and advanced of these tools is LoKast.

Created by Boris Bogatin, an engineering grad from the University of Pennsylvania, and now CEO of NearVerse, LoKast is unique in that it uses programming tricks to capture GPS and wireless data about which phones are actually nearby. Other location-based apps, such as WhosHere, are hit or miss: there is often a delay in sharing proximity data. But when I tested LoKast with two Sprint Evo Shift 4G smart phones in a variety of settings, including a crowded coffeehouse, its proximity engine worked quickly and reliably.