Why cross-device ad targeting is so promising -- and so challenging -- for mobile

Online marketers have long relied on cookies to track users’ behavior on the web in an effort to deliver targeted ads as accurately and effectively as possible.

But two major factors continue to minimize the relevance of cookies in mobile: Apple’s Safari browser doesn’t support third-party cookies, preventing advertisers from tracking users and retargeting pitches across multiple sites. Similarly, the webview technology used by native apps to display online content is unique per application, preventing the sharing of information between cookies or with the browser.

The latter problem is particularly troublesome because apps continue to dominate the time spent on smartphones. Apps accounted for an overwhelming 86 percent of the average US mobile consumer’s time in 2013, according to Flurry, while the web claimed a mere 14 percent, down from 20 percent in 2012. So while consumption of mobile data continues skyrocket, the mobile advertising industry still lags behind.