Derek Thompson of The Atlantic in this thought-provoking post claims four key problems are holding back the mobile advertising market: Advertisers don’t have enough information to deliver highly-targeted pitches; mobile screens are too small to present traditional Web-based ads (such as banners); marketers haven’t demonstrated sufficient innovation to overcome those small screens and digital may simply be too easy to ignore to generate real revenues.

All of those observations are valid, of course, and each continues to handcuff an industry that has failed to live up to a tremendous amount of hype. But Thompson only touches on conversion and ROI, which I think are the most important hurdles — and the biggest opportunities — in mobile advertising. While it’s not unusual for a consumer to see an ad for a product while surfing the web on a computer and buy it with just a few clicks, that behavior is far less likely to occur on a smartphone.

That’s why the concept of the mobile wallet holds so much promise for advertisers: It allows them to present themselves to users on the go, entice the user to enter the advertised business and consummate the purchase — all on their phones. That model enables advertisers to track their campaigns from the first point of contact all the way through the sale, providing a crystal-clear ROI of their marketing dollars. Many huge barriers must be overcome before that model gains any real traction, of course, and we’re still years away from the mobile wallet gaining mass-market adoption. The biggest challenge will be presenting ads that consumers actually want to receive and find valuable.