I completely agree with him on AirPlay's potential.<p>When AirPlay came out, I was thinking that it would be great to take advantage of it outside plain audio and video. I figured, if CPU allowed, it'd be possible to create a video stream on-the-fly with whatever UI you'd want in it and push it to the AppleTV. (I'm no hardcore developer, so this never went much further than a theoretical dream)<p>Then Apple announced AirPlay Mirroring, which is pretty much what I was thinking with the advantage (I believe) that it's managed in big part through hardware, making CPU usage lower, thus doable. My Twitter stream is witness of my excitement about that.<p>I'm convinced that when games start to really take advantage of it, this will give Apple access to gaming in the living-room. And not only racing games, first-person shooters, etc. but board games, games à la TV-game show, etc. Having two screens, one being private, can lead to very interesting apps and games. For example, you can have Pictionary/Taboo-style games where one player has an iPod with some info, and the rest is shared on the TV. And you can also take advantage of other iOS devices nearby.<p>Now, I was not convinced about Apple going to the expense of building TVs when the AppleTV (box) already has much of the benefits of what I would think an Apple TV set would do. But Joe made some good points about improving the current TVs: no need for a remote to turn on/off, no need to switch inputs, possibility to improve the network connection with the devices… (e.g. like AirDrop does with a dedicated channel between two Macs)<p>Finally, regarding his last line <i>"If I were an iOS developer, and I'd start investing in AirPlay right now."</i>, my understanding is that it's actually very simple to implement: <a href="https://developer.apple.com/library/safari/#documentation/AudioVideo/Conceptual/AirPlayGuide/EnrichYourAppforAirPlay/EnrichYourAppforAirPlay.html#//apple_ref/doc/uid/TP40011045-CH6-DontLinkElementID_7" rel="nofollow">https://developer.apple.com/library/safari/#documentation/Au...</a><p>You can get a notification of a second connected display and use that screen to build your UI in exactly the same way you would your main interface. The only thing that seems to defer is just the window object it's applied to.