• by Mark Walsh  @markfwal, June 8, 2011

New data released by comScore yesterday showed the number of mobile display advertisers in the last two years has more than doubled, to 689, as of April. That's based on its Ad Metrix Mobile, which tracks mobile display advertising across more than 600 of the top websites and "sub-sites" on the mobile Internet. The growth is encouraging -- but that's still off a very small base, a reminder why inventory still far outstrips demand in mobile advertising.

Half of the ads are also coming from endemic advertisers: mobile content and publishing companies. Non-mobile categories still only make up small segments of the mobile ad landscape, with industries such as financial services, information technology and consumer staples each accounting for 7% of total display ads. Even telecom only made up 5% of mobile ads. Don't they believe in their own medium?

More striking were comScore's findings underscoring the gap between feature phones and smartphones when it comes to mobile content and advertising. So while eight in 10 smartphone owners used a mobile browser, only 19% of people with regular cell phones did so during the first quarter of 2011. Similarly, 85% on the smartphone side used an app during that period, compared to only 16% on the feature phone side.

On the ad front, 27.5% of smartphone users saw a mobile Web or in-app ad, versus just 5% of feature phone users. And more than twice the percentage of feature phone users who responded to an ad did so on smartphones: that's 3.5%(feature phones) to 7.7% (smartphones).

The higher engagement level is mainly a factor of smartphone users' heavier browser and app use than those on feature phones. Overall, comScore estimates 31% of U.S. mobile users have a smartphone, up from 20% a year ago.

For marketers, the spread of smartphones can't come fast enough. Whether penetration of high-end devices will crack 50% this year as predicted by Nielsen, though, remains to be seen. The growth rate would have to accelerate over the second half of 2011 to reach that level. But it's clear smartphones (and tablets) are where mobile advertising will find the highest level of awareness and interaction, and the biggest payoff for marketers.