Facebook is the most popular mobile app in the U.S. in terms of unique users — at least for now.

The signature Facebook app passed Google Maps in October of last year to become the most used mobile app in the U.S. and held onto the top spot through the end of the year, according to data released Wednesday by comScore Mobile Metrix.

Facebook’s app enjoyed strong growth in 2012 with 85.5 million monthly unique users in the U.S. in December across iOS, Android and RIM’s mobile platforms, up from just under 65 million in March, when comScore first started tracking mobile app data. (In October, Facebook reported 604 million monthly mobile users worldwide.) Google Maps, on the other hand, saw its active user numbers dip from about 80 million in August and September to a little more than 70 million in October after it was removed as a default app on iOS 6.

“Both Google Maps and Facebook were growing nicely throughout the year until that happened,” Andrew Lipsman, VP of industry analysis at comScore, told Mashable. “Facebook continued that trend and Google Maps took a dip that one month and now it’s climbing back.” Google launched a new Maps app for iOS 6 in mid-December, and Lipsman says it’s likely Maps will grow its user numbers at a faster rate going forward, though it’s unclear whether and when the app will return to the top spot.

ComScore’s mobile app data is based on browsing behavior tracks from a panel of users as well as supplemental data from publishers showing app usage. The numbers represent active visitors to apps — rather than app downloads — similar to the way that comScore tracks visitors to websites.

While Facebook currently held the top spot at the end of the year, Google had the next five most used apps, including Google Maps, Gmail and YouTube. Lipsman credited this to the growth of Android and the popularity of Google services in general.

Aside from having the largest audience, Facebook’s app also has by far the highest level of engagement. According to comScore, Facebook’s app accounted for 23% of time spent on mobile apps while all of Google’s apps collectively account for 10% of time spent.

Pin It on Pinterest

Share This