Above all, Google does search. Sure, they do all sort of different thing but above all they do search, it's how they started and it's what they do best so it's not strange to see Google Search slowly becoming one of Android's pillars. When they added Google Now, it became an amazing tool and the knowledge graph makes it amazing at searching anything and giving you the best possible answer. However, when you search the web, what Google gives you is still a list of links, regardless what you have installed on your phone or tablet.
That's about to change thanks to app indexing which basically means that Google will integrate what's on your phone with the results you get when you do a search.
If you look for a movie, why would Google give you a link to IMDB.com when you have the IMDB app installed? That's exactly what's changing, from now on you'll get the same result with the addition of a button to go directly to the app.
Google refers to this as "deep link" and you'll see it as "Open in app" to the right of the screen with the name of the app on the left side. It will work even when the app is not the same as the result. As you can see in the image below, a search for Gravity gives you a rottentomatoes.com result but the deep link refers to Flixster. How does this work? Google explains the order of how this works in the Flixster example:
- The Flixster app supports deep linking
- The Rotten Tomatoes website has specified that the Flixster app page is an alternate for the web page
- Google has indexed the Flixster app to determine relevance
- The user has installed the Flixster app
App indexing will empower native apps over search results, giving users a more natural experience while doing searches on their devices. Here's a better look at app indexing by Nazmul Idris on this DevBytes video.
As of now Google is testing this with a limited amount of developers including AllTheCooks, AllTrails, Beautylish, Etsy, Expedia, Flixster, Healthtap, IMDb, moviefone, newegg, OpenTable, Trulia, and Wikipedia. You'll start seeing this deep link buttons in the US in a few weeks.