There is still a nagging feeling out there that mobile advertising is hard to do. That it will require yet another agency specialist like search does or a fully mature mobile site, but it doesn't.

Let's start with a few facts and figures: there are three times more mobile handsets in the U.S. than PCs. In fact, 76% of U.S. households own at least one mobile phone. There are twice as many more mobile subscribers than there are Internet users. Data usage is doubling every year.

Simply put, the mobile phone has become an indispensable device giving marketers access to target audiences 24x7. It doesn't take an economist to project that marketers cannot afford to ignore this channel for long.

Mobile advertising campaigns have gone far beyond the voting campaigns we're all familiar with from American Idol. Ads delivered to mobile devices can have direct response mechanisms such as calling a 1-800 number or entering a telephone number or email to receive more information, or drive traffic to an existing mobile site.

Targeting can be set by language, country, category or by search behavior (and in some cases, combinations of various targeting parameters.) And, contrary to popular belief, a mobile site is not necessary to run a campaign. Running a campaign is exceedingly easy. With online self-service features, it takes only three online steps: entering or uploading ad creative, setting a maximum cost per click and determining the call to action required of users.

Rather than thinking of mobile as a "new, unapproachable" channel, think of ways to tie it in to your current online or search campaigns. Most companies whether brand or direct response have found ways to intelligently and easily incorporate the mobile channel into their marketing mix. Some use it as a call to action on TV, print or online to drive mobile brand interactivity while others are simply driving interested audiences who happen to be on their mobile phone to a core sales-driven action such as calling a 1-800 number, driving subscription to an online newsletter, or to a mobile alert.

While seemingly in a nascent stage, the fact is mobile advertising is projected to grow from $1.5 billion in 2006 to $13.9 billion by 2011 (eMarketer, January, 2007). The reasons are simple: mobile advertising that delivers relevant and useful ads gives users immediate answers that are regarded as valuable content; advertisers can influence their audience during the "last mile" at the moment just before a purchase in the real world. The level of targetability and reach that mobile advertising can provide will become points of success for marketers and we're well beyond the early adoption stage.

Don't be the advertiser left behind.

This commentary is insightful. I recommend it to others.