Facebook and Google are dominating app use in the U.S. by Valentina Zarya @FortuneMagazine September 4, 2015, 12:51 PM EDT E-mail Tweet Facebook Linkedin Share icons In a not-totally-unexpected upset, Facebook Messenger has displaced YouTube as the second most-downloaded mobile application in the U.S., according to comScore. In the U.S., the two most popular apps are Facebook and Facebook Messenger, but Google accounts for five of the top 10 apps. On App Annie’s global list of iOS downloads, Facebook dominates with four apps in the top ten (the other two being WhatsApp — which just announced it has 900 million monthly users globally, and Instagram). Surprisingly, Apple had no apps in the U.S. top ten, though the Apple Maps was #11 on comScore’s list. Globally, however, it earned two spots on App Annie’s top ten list, with its Find my iPhone and iTunes U apps. Apple is also catching up to in the U.S. in terms of smartphone platform market share. In the three-month period ending in July 2015, its market share was up 1.1% to 44.2%, while Google’s was down 0.8% to 51.4%. Can Apple overtake the Android operating platform? Will Facebook ever acquire Snapchat to become the biggest app purveyor? And finally, which of these companies will ultimately come out on top? These are the questions of our times.