<i>If someone has the Facebook app then they&#x27;re not going to be heading there via Google.</i><p>On the other hand a lot of other searches contribute to the search volume and should track the popularity of Facebook, problems with the app, developers looking for API documentation, discussions of policy changes, people looking for jobs, news about the company and so on. So even if people are using the app the search volume should say something about the popularity. One thing I can imagine though is that a shift from the web to the app might decrease the search volume by such a large amount that it totally obscures the trend of the other kinds of searches I mentioned above.