In some cities the ride-sharing app and Uber service is ubiquitous. In others, it's actually illegal. While Uber's owners and cab drivers wrangle over legality and liability, you, as a mere citizen who needs a ride to or from the airport in some strange city, simply want to know what the deal is. At its core, Uber is just an app that you download to your smartphone and use to get a nearby Uber driver to come pick you up. While some taxi services are getting on board with these newfangled apps, most for-rent cars still wait at the taxi stand or require you give the service dispatch center a call in advance. Uber doesn't do that. It's also worth noting that Uber drivers won't respond if you do that cool whistle thing New Yorkers do in movies to hail a cab.