(CNN) -- Facebook and Google are battling it out to dominate your smartphone time and, for now, Facebook is winning. According to the latest stats from comScore, Facebook was the most popular mobile app in the United States in 2012. The Google Maps app held the top position until October, when Apple rolled out its latest mobile operating system, iOS 6, and replaced the built-in Google Maps app with its own, less accurate version. Of course, Facebook also had a hand in its own success. Its number of monthly unique visitors rose steadily over the course of the year. In August, the company rolled out a long overdue revamp of its iOS mobile app for iPhone and iPads, significantly speeding up the launch, scroll and browsing times. User reviews in Apple's App Store shot up as a result, and in December the company followed up with a better version of its Android app.
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Facebook had the most popular mobile app for Android and iOS combined in 2012
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Google Maps was in second place followed by five other Google apps
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Facebook had highest levels of engagement, with 23% of app time spent in the app
People aren't just opening their @placeholder app the most, they're spending astonishingly large chunks of time in the app, poking around and reading up on their friends.
The more interesting story in the coming year might be Google's rise to dominate all mobile platforms, not just its own @placeholder operating system.