• by Mark Walsh  @markfwal, June 3, 2011

In April, comScore announced its new "Total Universe" report promising tracking for a publisher's entire audience across mobile phones, apps, tablets and shared computers, as at Internet cafes. Today, the Web measurement firm released its first Total Universe data set in beta, offering a few examples of how adding mobile to the mix provides a more complete audience picture.

Among them was Internet radio service Pandora, which gets a big share of its users via mobile (including Web browsing on phones and tablets and via apps). How big? Its total audience in April was 31.8 million, 74% higher than its audience on home and work computers -- the desktop PC-based audience comScore has traditionally focused on.

Forty-two percent of that traffic is coming from mobile, and more are coming from mobile and tablets (20.7 million) than home and work PCs (18.2 million).

"To exclude the mobile media channel from Pandora's audience is to ignore the majority of its audience," stated a Friday blog post by Cameron Meierhoefer, EVP of analytics at comScore. "And while Pandora may still be somewhat of an outlier case, the example highlights the extent to which mobile can drive traffic for certain brands -- especially those whose value proposition largely relies on mobility, such as Internet radio. It's also an indication of where the digital landscape is headed."

Besides digital music services like Pandora, other online properties that get a lot of mobile use include Twitter, Skype, and Facebook. Other services with localized distribution, like Groupon, are increasingly expanding to mobile. Newspapers and magazines, meanwhile are seeking to build their audience via mobile apps and tablet-centric editions.

In that vein, comScore looked at how mobile added to the audience reach of major newspaper sites. The largest, NYTimes.com, gets 2.3% incremental reach via mobile. At the high end, among the five sites examined, was the L.A. Times site, which picked up 6.7% reach.

"What these data suggest for publishers is that their total audiences are being shortchanged if they do not account for mobile audiences, which provide access to more eyeballs. In most cases today that incremental reach may be less than 10%, which still should not be ignored," noted Meierhoefer's post. With a growing uptake of smartphones and tablets, the mobile proportion of the overall audience should continue to grow over time.

That doesn't mean all audiences will be valued the same by media buyers. The initial examples given by comScore also don't provide insight on time spent per session across different platforms. But the breakout of the total digital audience in one package should at least give agencies and advertisers a better sense of where the bulk of users are for a given property, and where the highest growth is taking place.