Despite the recent controversy regarding smartphone like the iPhone and Android-powered devices storing and transmitting the users location without their awareness, most of us willingly transmit our location by choice when we use services like Foursquare or Facebook Places.
Sometimes the accuracy of the reported location is laughably wrong by hundreds of feet or even several miles. This is usually because the location is being derived from something other than a GPS satellite (cell towers, WiFi access points) or we are seeing actual GPS errors due to a number of possible causes (satellite geometry, atmospheric effects, etc.).
However, when GPS accuracy is at expected levels (about 20 feet), it is nothing short of amazing and enables the many geo-location centric social networking services we use and enjoy. In the years to come, this accuracy may get even better. New GPS satellites called GPS IIF (aka GPS Block IIF) will eventually provide accuracy of 2 to 3 feet.
GPS satellites get a serious upgrade (Physorg.com)
The first GPS IIF satellite was launched last August. A second satellite is scheduled to go up sometime this year. Ten more GPS IIF satellites will eventually make an even dozen in space. Until then, we’ll remain happy with our accuracy of up to 20 feet of our actual position.