Back in 2012 I wrote about the private framework around Remote View Controllers, hinting that developers should keep this in front of their mind. Through iOS 8 this became extensions, and with the Apple Watch, this is the main interface for Apple Watch, at least until WWDC 2015.
On the Debug podcast episode 57 Guy & co mentioned that Apple TV is a prime target for extensions, and I agree, but let's think it over. For my case, I have a kid and no time to watch TV. I use the TV mainly to stream music just like I would with an Airport Express (why, oh why, is this not in the Airport Extreme and Time Capsules! And why, oh why, has the Apple TV and Airport Express not merged yet? And neither have they been updated in forever. Sigh....). What is a killer feature here, and I really did not expect this to be anything of interest when I bought it, is that if I turn the TV on while playing music, it will also show the most recent photos I've taken with my iPhone, which means up-to-date photos of my kid. That's really awesome, and makes both my wife and I stop, look and enjoy. Oh, and my boy likes it too. :-) The second big thing is AirPlay, being able to share my screen on the TV. And this is the niche that the Apple TV Extensions could carve out a niche in, as I see it.
Take Adobe Lightroom. I love that they have brought it to the iPad, as I have my 160k photos stored and arranged there since around Lightroom 2.0. There is tons I would want them to work on in the app, and of course, showing photos on the TV is a part of that. At the moment, my only choice is AirPlay, making what I do and what my parents see while visiting the same thing. We´ve had presentation tools like KeyNote and PowerPoint give us the option of separate screen output for ages, so this seems klunky today.
But when would the screen extension fire off? With extensions on your phone or mac it's easy, just fire when it seems appropriate. With the Apple Watch, if you're it's close by, you're wearing it and the phone can show stuff there. But with the AppleTV, most time when I'm nearby the TV is off, or it is not the source being displayed. So there needs to be some mechanism of alerting the app when it would be proper to use it, or for the app to request to be able to use this display.
That got me thinking, where else would I like content to be displayed? Sure, Google has shown that glasses is a valid target, HTC has shown the same for phone covers. I can imagine a lot of places, and not all places are places where I think Apple would get into. Would it be worth it to Apple to allow third parties hosting remote view controllers (sorry Apple Marketing, extensions). That would for instance open up the possibility that my window manufacturer could allow apps to project something into my window. Or refrigerator. Or whatever. Would that be a thing for Apple, just like with MFi, and would that give me as a customer value?
