Google has announced a new feature for AdSense mobile publishers, which lets them serve text and image ads on their sites, specifically optimized for high-end smartphones like the iPhone, Android devices, and the Palm Pre.

With the launch of the feature, publishers can run larger AdSense ads on these phones, whereas before, they could only serve smaller ads.

"High-end mobile phones, like iPhone, Android-powered devices and the Palm Pre, continue to grow — Gartner estimates that global sales of smartphones will soar by 27% in 2009, to 177 million units. Naturally, as a result more and more people are browsing the web on the go," says Google software engineer Danielle VanDyke. "Because these devices offer a browsing experience that is similar to desktop computers, advertising on smartphones is a natural extension for any AdWords campaign."

Google says the addition of this feature will help "nurture the smartphone ecosystem," by encouraging users to create more mobile content.

To make the feature work, Google introduced a new JavaScript snippet that’s optimized for mobile "to reduce latency" on high-end mobile phones. The snippet also allows publishers to select additional ad unit sizes from common AdSense formats.

"However, if you’re targeting all mobile devices, or if you’re unable to make changes to your website, you don’t have to update your AdSense code in order to enable larger AdSense ads to show on high-end devices," says VanDyke. "We’ll automatically detect if the user is browsing with a high-end phone, and instead of serving a smaller mobile WAP ad, we’ll return a larger ad optimized for high-end mobile devices."

The new feature certainly opens up new opportunities for AdSense publishers, who have had some additional benefits announced recently. Just the other day Google announced that it would extend YouTube promoted videos to AdSense for example. Google also recently announced the addition of ad networks to the competition pool for AdSense.

Social networks and companies with links to the mobile Internet may represent a perfect match.  The results of a survey from CCS Insight indicate that social networks are a significant factor in increased mobile Internet usage.

One important note: since the CCS Insight survey reached more than 1,000 UK residents between the ages of 16 and 35, its findings aren’t too likely to represent a statistical fluke.

Otherwise, an official statement explains, "Mobile Internet use is growing at a phenomenal rate; social networking is driving growth with a third of young adults regularly accessing Facebook and Twitter from their mobiles."  (Men do so at twice the rate of women.)

Paolo Pescatore, Head of Mobile Content at CCS Insight, also said, "Forget music downloads and video – social networking is what people want.  Media owners and operators will have to find new ways to make money from their assets."

Some of them seem to already be on the path, of course; think of the Sprint/Palm Pre/Facebook/Joanna Gikas commercial that’s airing right now.  What should be really interesting is to see how all of this ties together even more in the future.