Google announced incredibly important news not just for SEOs but for the future of their index and ranking reach.
Google is now ranking content within apps that do not have web content matches. Let me explain that better, which I normally wouldn't bother doing, but this is important. Previously, Google would only rank content within an app, if there was a canonical version of the app page on the mobile web. So with Yelp, if it had a restaurant listing in their app for In and Out Burger in San Jose, it would only rank that app listing if Yelp also had the web alternative URL for it.
Now, that is no longer required, at least for Android apps. As long as you are using Google App Indexing API, Google will do their best to understand the content within your app and rank it in the search results even without it having a web URL. Again, this is only Android right now and honestly, it is only English US results for nine apps including Chimani, Daily Horoscope, Gormey, Hotel Tonight, My Horoscope, New York Subway, Useful Knots, Visual Anatomy Free and Weather Channel. But Google does plan to roll this out more widely if these initial tests prove well.
How Do I Get Included?
You don't. You wait. Make sure your Android app has App Indexing API integrated in it and wait. When Google pushes this out to every app, you won't have to do anything Google tells me. It will just work without any more work.
So deploy the app indexing API.
What If I Don't Have The App Installed?
This is the crazy part, Google built a streamer, a player, that will stream your Android app to Android searchers if they do not have your app installed. Well, most searchers, they need Android L or higher and a solid Wifi connection. The streamer will show a "stream" button in the search results and when clicked, will launch the player. It looks like this:
You need to understand how important this is. This will get your app, in its full state, running on any users Android device, even if they did not install it. The hope, users will eventually install the native app on your device. If not, there is nothing stopping the user from using your app in stream mode fully, Google tells me.
Of course, app content ranking is becoming more and more important. The primary key with that is simple, use the Google App Indexing API and make a great app.
I have a heck of a lot more detail on this on my story from yesterday on Search Engine Land.
In short, this is massive news and will only continue to become more and more important in 2016.
Forum discussion at WebmasterWorld and Google+.