Chris Cameron. ReadWriteWeb - June 24, 2010 -- Wait, what the heck is geofencing? No, it's not some virtual sword fighting app for your phone. Geofencing, or a geofence, is exactly what its name implies - a virtually fenced-off geographic location. When this concept is applied to mobile phones, it refers to a device's ability to receive automatic alerts or notifications when entering, leaving or moving within a specific geographic area. Location Labs, providers of location services for mobile developers, announced earlier this week the release of its library that will allow iPhone developers to build geofencing apps thanks in no small part to new features included in the new iOS 4.0.