As usage of the Internet on mobile devices like the Apple iPhone has become more prevalent, many businesses have been wondering how important it is for them to cater to these users through the creation of web sites that are optimized for mobile display.

Although creating a mobile version of a web site doesn’t have to be a major undertaking, it is “yet another task” to add to the marketer’s never-ending to-do list. So, just how important is it?

Chitika, Inc., a Massachusetts-based online advertising network, has analyzed the behaviors of “mobilists” and found some interesting results when it comes to their viewing of advertising and taking action. In tracking more than 92 million ad impressions served up by browsers, it turns out that mobile internet users clicked through at a far lower rate than those viewing ads on desktop machines.

How much lower? The overall clickthrough rate for mobilists was 0.48%, compared to a clickthrough rate of 0.84% for non-mobile users. That’s a serious difference, and gets about as far in the basement as you can go.

But why are the numbers so abysmal? More than likely, several factors are at work. First, consider the ways people use their mobile devices. It’s usually because they want to know something immediately … and it’s at times like those that folks are less inclined to get sidetracked by clicking on advertising links. By contrast, the “immediacy” factor with non-mobile devices often isn’t as acute.

Also, consider the load time on mobile devices – rather much slower. For that reason, mobile web content tends to be less informationally rich — or compelling in its appearance — thus decreasing its “stopping” power.

What this means for advertisers is that the key for succeeding in the mobile space is catching consumers at just the right time, not happening to catch them at any time. Easy enough in theory … but would anyone care to volunteer for putting this into practice? Best of luck to you.

From the perspective of the media purveyors, the Chitika findings certainly won’t make their task of attracting additional advertising revenues in the mobile sector any easier. Perhaps that’s why The Wall Street Journal announced last week that, beginning in November, it will be charging mobile users a weekly fee to access its content on mobile devices – and those fees will be charged to WSJ subscribers and non-subscribers both.

It’s further proof that relying on display advertising revenue simply isn’t cutting it as a practical business model in the mobile environment.