The Internet isn’t flat anymore (was it ever?). It is not an extensive network of interconnected websites, which Google can easily crawl and rank.
With the introduction of mobile devices, users are browsing through different layers. They can search for “family vacations in San Francisco” in the browser, get results from Google, click on a link and being redirected to the San Francisco’s section in the TripAdvisor app.
The type of link between the browser and an already-installed mobile app its called Deep Link. If you are on mobile right now and have the Twitter app installed, try this link: twitter://user?screen_name=leocelis
If you didn’t have the Twitter app installed, you would be prompted to download it, and once it’s ready, you will be redirected to my profile. That’s what we call a Deferred Deep Link.