Despite our intuition that we should remove the interstitial, we prefer to let data guide our decisions, so we set out to learn how the interstitial affected our users.
Our analysis found that:9% of the visits to our interstitial page resulted in the ‘Get App’ button being pressed. (Note that some percentage of these users already have the app installed or may never follow through with the app store download.)
69% of the visits abandoned our page. These users neither went to the app store nor continued to our mobile website.
Sixty-nine percent of visitors said “fuck this”, and closed the window.
Source: Official Google Webmaster Central Blog: Google+: A case study on App Download Interstitials