YoCheckIn enables the seamless sharing of your location with several people via SMS by sending a yo. Subscribe to YoCheckIn by sending a yo to YOCHECKIN, add up to 5 valid cellphone numbers with whom you want to share your location, and then share your location with these numbers at any given time by simply sending a yo. You can update the numbers with whom you would like to share your location at any given time by going to www.yocheckin.appspot.com.
Applications include kids sharing their location with their parents or guardians, friends meeting up or trying to invite each other to events that are quickly changing location, and infinitely more exist. It extends the ability to yo people who do not have the app. The power and extensibility all reside in its simplicity.