Android Candy: Waze
I have a love/hate relationship with Waze. The idea of peer collaboration regarding traffic, combined with the technology to accomplish it on an enormous scale is truly amazing. Yet, every time I've used Waze myself, it's been an exercise in frustration. It has insisted I turn left off a bridge, and then it refused to reroute me when I didn't. On one trip, it had me get off every freeway exit, only to get back on the freeway immediately with the adjacent onramp. That doesn't seem to be the case for everyone, and perhaps it's simply because I live in a fairly rural area, and there aren't many users apart from me in the area.
Waze is a turn-by-turn GPS application. For most people, it works well and gives quick and easy directions to get from point A to point B. It also has a very robust social aspect, which is really what sets it apart. Did you just pass a police officer setting up a speed trap? Click on the Waze app, and it will warn fellow Waze users as they approach. Is there an accident? Tell Waze about it, and it will warn other users and route them around the slowdown.
There is a certain competitive aspect to Waze as well. Who has mapped the most new roads? How many miles have you driven with Waze? From a mapping aspect, the truly amazing part of the entire system is that Waze watches the routes you take and uses that information to guide others. For that reason, Waze prefers you have the app running whenever you're on the road, whether or not you need it for guidance. Your driving adds to the routing algorithms, ideally making things easier for other drivers in the future.
Waze is available at the Google Play store: https://play.google.com/store/apps/details?id=com.waze. Check it out for yourself and see if the navigator in your phone is awesome, or if it wants to murder you, like mine does for me.