Last week, Google made two announcements about how it will rank search results on mobile devices going forward. The one that has received the greatest amount of attention is the inclusion of a mobile-friendly ranking signal, which will go into effect beginning April 21. This gives sites time to make sure their sites meet Googles criteria for being mobile-friendly, and to avoid a potential rankings hit. More on how to make your site more mobile-friendly here.

The other announcement was that Google is now using information from indexed apps as a ranking factor for signed-in users who have the app installed. That’s already in effect.

Do you have an Android app? Do you have it set up for app indexing? Let us know in the comments.

Google said that as a result of this particular factor, it may now surface content from indexed apps more prominently in search.

Google first began testing app indexing in the fall of 2013. Googlebot began indexing content in Android apps, and gave webmasters the ability to let Google know which app they’d like Google to index through their existing sitemaps file and through Webmaster tools.

As the company explained at the time:

“Searchers on smartphones experience many speed bumps that can slow them down. For example, any time they need to change context from a web page to an app, or vice versa, users are likely to encounter redirects, pop-up dialogs, and extra swipes and taps. Wouldn’t it be cool if you could give your users the choice of viewing your content either on the website or via your app, both straight from Google’s search results?”

“If both the webpage and the app contents are successfully indexed, Google will then try to show deep links to your app straight in our search results when we think they’re relevant for the user’s query and if the user has the app installed. When users tap on these deep links, your app will launch and take them directly to the content they need.”

Google said back then that app indexing would not impact ranking. Now it does.

At first, Google only indexed a select few apps, including Allthecooks, AllTrails, Beautylish, Etsy, Expedia, Flixster, Healthtap, IMDB, Moviefone, Newegg, OpenTable, and Trulia. Last April, Google announced that it had enabled it for over 24 more applications, including: 500px, AOL, BigOven, Bleacher Report, Booking.com, Eventbrite, Glassdoor, Goodreads, Huffington Post, Merriam-Webster, Pinterest, Realtor.com, Seeking Alpha, TalkAndroid, TheFreeDictionary, The Journal, TripAdvisor, Tumblr, Urbanspoon, Wattpad, YP, Zagat, Zappos and Zillow.

They also made it available globally in English. The following month, they made it available in more languages. At Google I/O last year, they announced a slew of additional apps, and opened app indexing up to all Android developers. If you have an Android app, you can participate. At the time, they also made some design tweaks to how apps appear.

Also at Google I/O, the company held a session called “The Future of Apps and Search,” which discussed bringing search and apps together to give users a better experience. In light of the ranking news, you might want to give that a watch if you don’t already have app indexing implemented.

Here’s a much shorter overview on getting your app in the Google index:

In December, Google said clicks on app deep links jumped by 10x the prior quarter, with 15% of signed-in Google searches on Android now returning deep links. These numbers have likely only increased since then.

There are four basic steps for enabling users who have your app installed to open your content within the app from Google search results: add deep link support, verify your app’s official site on the Google Play Console, provide deep links, and check for errors in Webmaster Tools, so you can fix them.

You can find the documentation for adding deep linking support here. You have to specify intent filters in your app manifest that define how to reach specific content inside your app. Google walks you through this process in that link.

You’ll then want to test your deep links using the Android Debug Bridge, which is a command line tool that lets you communicate with an emulator instance or connected Android-powered device.

You’ll also want to restrict access to parts of your app content. This involves including a noindex.xml file in your app to indicate which deep links shouldn’t be indexed. You’ll be able to specify a list of URIs to exclude, or a list of URI prefixes. As Google notes, it’s similar to how the robots noindex meta tag works for websites.

After you’ve added support, you’ll need to verify your website. Sign in to your Google Play Developer Console, click All Applications, select the app you want to verify, and select Services & APIs from the left menu. Under “App Indexing from Gogole Search,” cliick “Verify website.” Type your web address, and click “Verify”. Then, go to Webmaster Tools (requires “owner” permissions), and click “All Messages” from the left menu. Open the verification request message, approve it, and then your app will appear on the Associates page of your WMT account. You can then provide deep links for each web page that has a corresponding deep link.

After verification, you’ll want to provide deep links for each page that has a corresponding deep link either on each page of your site or in your sitemaps. You can ffind documentation on this here.

When adding deep links to your sitemap or webiste, Google says they should only be included for canonical web URLs, and to remember to specify an app deep link for your homepage. Not all website URLs in a sitemap need to have a corresponding app deep link, don’t include them for those that aren’t supported by your app. News sites using News Sitemaps should include deep link annotations in them as well as in general sitemaps. Google also says not to provide annotations for deep links that execute native ARM code. This enables app indexing to work for all platforms, it says.

“When Google indexes content from your app, your app will need to make HTTP requests that it usually makes under normal operation,” Google’s Michael Xu said in a blog post last April. “These requests will appear to your servers as originating from Googlebot. Therefore, your server’s robots.txt file must be configured properly to allow these requests. Finally, please make sure the back button behavior of your app leads directly back to the search results page.”

Information related to app indexing that Google shows in Webmaster Tools includes: errors in indexed pages within apps, weekly clicks and impressions from app deep links via Google search; and stats on your sitemap (if that’s how you implemented the app deep links). Google says it will be adding a lot more.

There are two new ways to track performance for your app deep links. Google will send a weekly clicks and impressions update to the Message center in in WMT, and you can now track how much traffic app deep links drive to your app using referrer information (referrer extra in the ACTION_VIEW intent). The company said in December it was working to integrate this info with Google Analytics.

“Blocked resources are one of the top reasons for the ‘content mismatch’ errors you see in Webmaster Tools’ Crawl Errors report,” said Google Webmaster Trends analyst Mariya Moeva. “We need access to all the resources necessary to render your app page. This allows us to assess whether your associated web page has the same content as your app page.”

“To help you identify errors when indexing your app, we’ll send you messages for all app errors we detect, and will also display most of them in the ‘Android apps’ tab of the Crawl errors report,” Moeva said.

At the time, Google announced three new error types that go along with the existing “content mismatch” and “intent URI not supported” error alerts: APK not found, no first-click free, and back button violation.

Google has an app indexing “codelab” tutorial available here. This will walk you through running a sample app, opening a starter project, identifying deep links, adding intent filters, adding code to handle intent filters, testing intent filters, verifying the Google Play Service version, creating an API client, recording a page view, recording a page view end, testing Autocomplete in Google Search, adding app indexing markup, connecting the app using Google Play Console, verifying the app in Webmaster Tools, and updating robots.txt.

Apps with or without corresponding webpages can use the App Indexing API to notify Google of their deep links. Documentation for this is available here.

There’s also an app indexing checklist here. Additionally, you may want to peruse the FAQ.

For now, Google only supports Android apps for app indexing. While it’s missing a huge chunk of popular apps by not supporting iOS, Android does dominate smart device operating system market share, mainly due to its wide use across a plethora of devices. According to new research from ABI, Android holds 53% of that market share.

In other words, that’s a lot of potential visibility for app content in Google search results. It’s also possible that Google will eventually support iOS apps.

“You’d have to imagine Google will bring support, despite Apple not probably making it easy, to iOS devices,” wrote Search Engine Roundtable’s Barry Schwartz in December, as he pointed to a hint that Google may do just that.

It’s not a major hint, but a Googler responded to a question in a Webmaster Help forum thread, saying, “app indexing is supported only for Android for now. Stay tuned for updates (:”

Beyond making the content from existing Android apps more visible with its new ranking signal, it’s likely that the move will inspire more companies to create Android apps in the first place.

Last week, Google announced the launch of paid search results in Google Play, which will also help app makers gain more exposure. This is only in the pilot stage for now, but will likely become a major feature available to Android users and advertisers.

Google also won a bidding war for the .App TLD. It’s unclear what Google intends to do with that at this point.

Are you taking advantage of Google’s app indexing? If so, have you noticed any ranking changes? If not, do you intend to? Discuss.

Images via Google