AirPlay is a technology that seamlessly moves audio and video from device to device in the Apple ecosystem. It's built into the iPhone, iPad, and -- most importantly -- the Apple TV set-top box. Among other things, AirPlay can be used to send video from iPhone apps like YouTube, MLB.tv, or WatchESPN to the AppleTV.
Apple hasn't advertised AirPlay as strongly as some other features, like the iPhone 4S's Siri, though it did run a television ad after the iPhone 4 was introduced in 2011. That said, it's surprising that Glenn A. Britt, the chief executive of Time Warner Cable said he hadn't heard of the service, according to the New York Times.
"I’m not sure I know what AirPlay is," he said, though he noted that he was an enthusiastic Apple customer. "Today we want to be on every screen. Today it’s a little bit clunky to get programming from the Internet onto the TV — not so hard to get it on your iPad. What’s hard is the plumbing, what wires do you connect, what device do you use. So the current Apple TV, the little thing, the hockey puck, really doesn’t do anything to help enable you to get Internet material on your TV."
Ironically, Apple has solved Britt's problem -- though he wasn't aware of it -- but the company is not pushing AirPlay too strongly upon its users, nor the media companies. The Apple TV natively supports only a handful of third party services like streaming MLB, NHL, and NBA games, as well as Netflix.
However, AirPlay support has allowed many apps to send "programming from the Internet onto the TV", just as Britt wants, and could foreshadow the market segment a rumored Apple television set would fill.