loopt is a Palo Alto-based startup that has built a revolutionary "social mapping" service to change the way people use mobile phones to keep in touch with their friends. loopt uses GPS (and other location technology) to show you where your friends are by automatically updating maps on your mobile handset. loopt also lets you send messages to nearby friends or receive automatic alerts when they're nearby so that you never miss an opportunity to meet. With loopt, mobile subscribers put themselves on the map.