I've been a frequent user and a big fan of Glympse ever since I first reviewed it. If you're on a trip, meeting someone for lunch and so on, you can share your location in real time, along with your ETA and your route. It's a clever marriage of iOS and GPS. The Glympse app is free, and has had many worthwhile updates and improvements.
Today, Glympse announced a partnership with Mercedes-Benz to provide a first-of-its-kind offering that gives users realtime location sharing right in their cars. Drivers will be able to use the in-dash Mercedes DriveStyle to select a recipient, set a timer, and "send a Glympse" to anyone they choose. The recipient receives a text or email link with the driver's real-time location on an interactive map. When the timer expires, the location sharing will automatically stop. Because Glympse is a universal sharing solution, the recipient doesn't require any special software or device. A web browser will do.
Having the feature built into a car has the obvious advantage of saving on battery on your iPhone. With the GPS chip sending your data on a second-by-second interval, I always use Glympse with my iPhone plugged into a charger.
BMW has something similar, but it is much more primitive. You send an email to someone from the car and it gives them your location. No mobile phone required. But the location is not updated in real time, and you have to keep sending it. Nothing I want to fool with while driving.
Glympse stores an address book, and even has templates for frequent destinations. It is easy to set up, and you do that before you go on the road. Mercedes will get similar capabilities as part of the car telematics. No mobile phone needed.
This feature will appear in new Mercedes A-Class cars, and I expect it will expand through the model line. I'm sure discussions with other auto makers are in progress. Of course you don't need a Mercedes to use Glympse. Just grab it from the iOS app store and you are literally on your way.