Use deep links to bring your users into your apps from social posts, search, or ads.
Deep Linking from Google+ Posts
Deep linking allows the Google+ apps on mobile devices to direct clicks on a shared post that contains deep-link information to a resource within your apps.
If the user doesn’t have your app installed, they’re prompted to install it before accessing the resource.
G+ Post with Deep Link to Buy
Purchase page within app
Deep Linking from Google Search — App Indexing
Another way to bring users back to your apps is to apply for app indexing.
When a user searches for content available within your app, Google can show an "Open in App" button in in mobile search results. For instance, if a user searches for a restaurant and you’ve got that establishment in your dining app, a link can be shown to open the page within your app. Learn more about linking to in-app content.
Deep Linking from Google Ads
Ads can remind users about the apps they already have.
As with deep links from Google's organic search results, AdWords deep links send users directly to the relevant pages in apps they already have on their mobile device. A mobile search for "flights to London," for instance, could take a user straight to the London page in a travel app. Learn more.