Mobile advertising may not be foremost on the minds of today's marketers, but those who ignore the mobile web do so at their own peril.

The mobile advertising revolution may be one of the most over-hyped promises of the digital age, but Tony Nethercutt, AdMob's VP of sales, has a lot of experience with selling space when most marketers are pretty sure there's nothing out there but hype.

Nethercutt, whose career in digital sales dates back to the early days of Yahoo and DoubleClick, said today's mobile space isn't all that different from the internet a decade earlier.

"Mobile is the internet circa 1997 in terms of selling space," Nethercutt told attendees at the iMedia Agency Summit in Austin, Texas. "That means that a lot of what we do is educate our clients and agencies about what mobile means and why it's important for them to experiment in the space now."

For Nethercutt, the goal of a sales call isn't to get a client to divert gobs of money to mobile -- though that would be nice -- it's to make mobile an extension of the brand's digital campaign.

"What we've seen from advertisers who test the waters in the mobile space is that they go from something small to something bigger with each new campaign," Nethercutt said. "So one of the best things you can do for your client is test small because that can help you determine what you need to be doing in mobile."

According to Nethercutt, the approximately 40 million U.S. mobile users are highly engaged with the ads in the space at a rate of 10 times what is commonly found on the internet. At the same time, the mobile space is growing at 40 percent per year, and the high recall rate for mobile ads indicates that the medium is well suited to both branding and direct response.

But there's another bonus to advertising on mobile -- the user is something of a captive audience.

"On the web, there are a lot more things competing for the users' attention; mobile is a small space," Nethercutt said. "Because it's such a tiny screen, users aren't bombarded with a lot of other stuff."

But it's more than just the attention span of the medium's users that has Nethercutt and his AdMob colleagues high on mobile. Although mobile advertising in the United States is still very much in its infancy, Nethercutt said AdMob has already delivered some impressive results for advertisers.

Working with Land Rover, AdMob helped the carmaker create an ad for the iPhone that literally put the prospects of a test drive at the users' fingertips.

The ad, which AdMob distributed through its 4,500-strong network of mobile-optimized sites, allowed users to schedule a test drive by calling a local dealer, use Google Maps to find their nearest dealer or visit the company's mobile site for more information.

According to Nethercutt, the ad generated better-than-expected leads for the local dealerships' sales teams. But, he pointed out, the campaign could just have easily been created to help the carmaker's branding efforts. For now, though, Nethercutt said he's happy to see brands like Land Rover learning the mobile ropes.

Michael Estrin is associate editor at iMediaConnection.