• by Mark Walsh  @markfwal, May 7, 2012

Google ranked as the top smartphone property in March, with 94 million unique visitors -- representing 97% reach of the U.S. mobile audience, according to new data from comScore. Facebook was second across both the mobile Web and apps, with 78 million monthly visitors, followed by Yahoo (66 million), Amazon (44 million) and Wikipedia (39 million).

Other top properties included eBay, The Weather Channel, Rovio (“Angry Birds”) and ESPN.

Facebook, not surprisingly, was also the dominant social networking service on smartphones. Placing a distant second behind its audience of 78 million (80.4% reach) was Twitter, with 25.6 million, LinkedIn (7.6 million), Pinterest (7.5 million), Foursquare (5.5 million) and Tumblr (4.5 million).

The social network also made the top five among mobile apps on Apple’s iOS and Google’s Android platform. On the iOS side, iTunes itself ranked as the leading app with 32.6 million unique visitors, reaching nearly the entire iPhone app audience. Following the system app were Google Maps, with an audience of 29.8 million, Facebook (26.1 million), YouTube (25.5 million) and Yahoo Weather (23 million).

For Android, the Android Market was the top app, with an audience of 49.7 million, or 93.2% reach -- followed by Google Search (44.8 million), Google Maps (39.8 million), Gmail (38.1 million) and Facebook (36.7 million). The Zynga game “Words With Friends” also made the top 10 app lists on both smartphone platforms.

comScore released the findings in relation to introducing the latest version of its Mobile Metrix service, which extends the Web tracking firm’s Unified Digital Measurement offering to smartphones. That service combines on-device panel measurement with server-based data to show mobile media usage across apps and mobile browsing.

The upgraded service provides mobile audience data akin to the rankings that comScore has long provided for the desktop Web. “This completely retooled and enhanced version of the service is the mobile analog to comScore’s flagship Media Metrix product, bringing critical insights such as audience size and demographics to the mobile marketplace,” said Mark Donovan, comScore SVP of mobile.

In addition to total audience and reach, the new mobile research also reveals the split between time spent in apps and the mobile Web for top smartphone properties. The results underscored that apps account for the vast majority, representing 4 of every 5 mobile media minutes. But the Web/app split varied among top properties.

On Facebook -- the top property by engagement at more than 7 hours in March -- 80% of time spent was on apps compared to 20% via browser. Twitter had an even higher percentage of time spent with apps, at 96.5% of all minutes. Microsoft, by contrast, was among brands that saw browser access driving a majority of usage, at 82.1%. Similarly, virtually all of time spent on Wikipedia, was through the mobile Web.

Among the other points the smartphone research highlights is the emergence of Pinterest as a social networking force -- not only on the desktop but also in mobile. The visually focused social site has already surged past Foursquare and Tumblr on smartphones and is closing in on LinkedIn, with Pinterest’s 7.5 million monthly visitors representing 7.7% reach.

comScore derived the overall audience data from browser and app use on BlackBerry smartphones as well as the iPhone and Android devices.