• by Gavin O'Malley , Staff Writer @mp_gavin, September 4, 2015

Mobile use is a-changin’--and increasingly, in Facebook’s favor. For the first time ever, the social giant's Messenger app has surpassed Google’s YouTube app in popularity, according to fresh findings from comScore.

In July, Facebook’s popular messaging app took a 59.5% reach, edging out YouTube’s 59.3% share.

Albeit by a tiny margin, the lead represents a huge win for Facebook and its effort to diversify its app portfolio.

Don’t feel too bad for Google, though. In terms of reach, Google Search, Google Play, Google Maps, and Gmail ranked in fourth, fifth, sixth and eighth place, respectively.

Overall, Facebook’s flagship app continues to dominate the field with a 73.3% reach, but the company has never been comfortable putting its proverbial eggs in one basket.

As such, Facebook boldly asked more than 1 billion users to install the messaging service as a separate mobile app last year. At the time, CEO Mark Zuckerberg admitted that it was a “big ask.”

Some in the industry have seen the focus on Messenger as highly defensive. “Messenger is Facebook’s answer to the growing concern of the younger generation abandoning Facebook, the social network, for messaging apps like Snapchat,” Greg Ratner, director of technology at Deep Focus, recently told us.

Defensive or not, the efforts are clearly paying off. Just three months after the initial change, Messenger has been downloaded more than 500 million times. More recently, Messenger surpassed 1 billion downloads among Android users alone.

More broadly, comScore found that smartphone penetration among U.S. consumers has reached 77%.