• by Mark Walsh  @markfwal, October 8, 2014

YouTube is moving into the mobile spotlight. The latest comScore figures for mobile apps released Tuesday show that the video hub in August had 55% reach among U.S. smartphone users -- second only to Facebook, at 72.4%. YouTube’s share of reach is up from about 48% six months ago, highlighting the growing audience for video on smartphones.

Nielsen estimates the U.S. mobile video audience at nearly 115 million in the second quarter, up 18% from a year ago. Time spent per month is still minimal compared to TV and the PC at one hour -- 41 minutes -- but that’s up about 30% from a year earlier.

What’s also interesting is that YouTube has pushed passed other more utility-focused Google apps including Search, Google Play, Gmail and Google Maps. Further, its rise has come despite a low App Store rating relative to its sister apps. The YouTube iPhone app has only a 2.5-star rating (based on 126,000-plus ratings), compared to Search (3.5 stars), Google Maps (4.5 stars), and Gmail (3.5 stars).

Whether a more highly rated YouTube app would also have an even larger audience is hard to say. But a similar pattern is seen with the Facebook Messenger app. Since Facebook began requiring people to use the stand-alone Messenger app for all mobile chat this summer, the app has shot to 45% reach from just 29% back in February.

That rapid adoption comes despite a user backlash over Facebook removing the messaging function from the main app and a mere 1.5-star rating in the App Store. The reviews indicate the low rating is mainly a reflection of the anger over having to download a separate app to use a feature that was formerly part of the core app.

With platforms becoming as powerful as YouTube and Facebook, people may complain but still end up getting on board with their products because of the network lock-in effect or having few other alternatives. Whether YouTube can make further inroads on the dominance of Facebook’s main app will be something to watch as both companies increasingly vie for video ad dollars.

The new app ranking also points to an incipient dual in the music category, where Pandora has long reigned as the top player in online streaming, which now mostly means mobile streaming. Its app ranked No. 7, with 45% reach in August, but Apple’s iTunes Radio app just made the list of top 15 apps, with 21.7% reach.

Pandora hasn’t lost ground in share of reach in the year since iTunes Radio launched, but the Apple service has moved up the app chart in that time. And with Apple’s increased focus on the category, reflected in its $3 billion purchase of Beats Music this spring, iTunes Radio isn’t going away.