• by Mark Walsh  @markfwal, September 13, 2010

Android users are more likely to click on ads within apps than people using other mobile operating systems, according to a new report on mobile applications by the Nielsen Company. One-third of Android users have clicked on an in-app ad compared to 29% for those with Windows Mobile, Apple's iOS, 26%, Palm, 22%, BlackBerry, 15%, and other types of operating systems, 24%.

The Nielsen study, released Monday in connection with the AppNation conference in San Francisco, suggests that the higher click-through rate for Android-based ads may stem from the Google platform attracting a younger audience that is more receptive to mobile ads. Android's less affluent users also show a decided preference for free apps.

"Either way, they are more likely to click on an ad within an app, and that spells a clear monetization strategy for anyone targeting the fast-growing Android user base," concludes the Nielsen white paper, whose findings are based on an August survey of 4,000 mobile subscribers who had downloaded an app in the last 30 days.

When it comes to the popularity of individual apps, Facebook was at or near the top across all operating systems, underscoring the social networks' rapid mobile growth. The company says more than 150 million people worldwide are connecting to Facebook via mobile devices. Twitter was among the top five most popular apps only on BlackBerry, possibly because the device is optimized for typing.

YouTube is popular on Android and Windows Mobile, but doesn't make the top five on the iPhone or BlackBerry. iTunes, of course, rates highly only among iPhone owners.

Among broad categories, games remain the most popular apps among both smartphone and feature phone users -- at 61% and 52%, respectively, followed by weather apps. While apps generally find a higher proportion of uptake on smartphones than on regular phones, the difference is especially pronounced in certain categories like maps and navigation "where more computing power, larger screens and touch interfaces deliver a more satisfying experience," according to Nielsen.

So about half of smartphone users had downloaded a navigation-related or social networking app in the last 30 days compared to only about 30% of feature phone owners. People with either type of phone typically learn about apps by searching the app store on their device or through a recommendation for a friend or family member.

Nielsen also found that ratings and reviews are useful in deciding what titles to select: 18% of all downloaders say these tools are "extremely important," 36% say they're "very important," and 34% say "somewhat important." "Those seeking to market mobile apps would be well-advised to emphasize two tactics: Word-of-mouth marketing (including social media) and securing favorable ratings and reviews," stated the report.

Looking at free versus paid apps, iPhone owners report that for every two free apps they download from Apple's App Store, they typically pay for one. By contrast, people who frequent the Android Market and BlackBerry App World stores download more than 3.5 free apps for every one they buy. BlackBerry owners were also the least likely to convert from a free, "lite" version to a full paid one.

The BlackBerry storefront offers only about 10,000 apps compared to 80,000 for the Android Market and 250,000 for the App Store. BlackBerry-maker Research in Motion has recently attempted to boost demand for apps by revamping App World, dropping the $2.99 minimum price for titles, and introducing a new OS and new devices including the Torch.

Regardless of platform, when people do buy apps, they prefer to have charges appear on cell phone or credit card bills for convenience and security reasons.

Not surprisingly, the study showed that younger mobile subscribers are less averse to seeing ads on their devices than older ones. Teens are the most amenable, with 58% saying they "always" or "sometimes" look at mobile ads. That figure shrinks to 28% for those 55 and over. Overall, men of all ages are more receptive to mobile ads than women.

About one in five app users have gone to a search engine or looked elsewhere online for more information after viewing a mobile ad, or told someone about the advertised product or service. Sixteen percent have used a coupon and 14% have entered a contest or sweepstakes in connection with a mobile ad.

Assessing the mobile landscape for apps beyond smartphones, Nielsen found the iPod touch is the most popular "connected device" for downloads, with 16% choosing that option. Following the iPod is the Sony PSP, 8%, the iPad, 6%, e-readers, 5%, and Microsoft Zune, 1%. Considering that the iPad is the newest of these devices, its third-place ranking after less than six months on the market suggests it could eventually outpace its smaller cousin as an app platform.

Across all connected devices, games are the most popular apps -- just as on smartphones and feature phones, according to the Nielsen report.