By Kim Ann King

Every marketer has a Web site, but what about a mobile-optimized Web site? Mobile devices are an important and growing channel for business. Consider these statistics:

? According to mobiThinking, there are now more than 1.2 billion mobile Web users worldwide who account for more than 8 percent of Web traffic
? ComScore reports that mobile devices drove 10.8 percent of traffic to online retail sites on Cyber Monday 2011, more than double the previous year
? Interestingly, mobile devices accounted for even more online traffic on Black Friday ? 14.3 percent
? The most popular device for mobile commerce? The iPad

Clearly, with the ongoing proliferation of browsers and devices that can access your content and commerce offerings, the mobile Web opens up a vast new audience of potential visitors to your site.

In fact, Gartner predicts mobile will be the number one Internet access device as early as next year.

So the question becomes, what are you doing to optimize your mobile Web site?

Your standard Web site may be performing extremely well, but you will need to re-think what constitutes a successful site when you dive into the mobile Web, because mobile is different.

Analyses of consumer behavior have shown that mobile users have different needs and expectations than desktop users.

The ?on-the-go? environment, task-at-hand, and physical device constraints all differ, often dramatically.

Optimize without boundaries
Where to start? The top priority for mobile must be to provide a compelling user experience.

There is no magic bullet to creating a mobile site that attracts and converts traffic, so the best way to understand how to create a compelling mobile site is to experiment.

Mobile optimization using A/B and multivariate testing has been proven to be one of the most effective and immediate experimentation methods to increase sales, enhance visitor engagement and encourage content consumption.

Common methods for running controlled experiments on both Web sites and mobile sites range from simple A/B testing to sophisticated multivariate testing.

In A/B testing, one or more new versions of a page or single element compete against the original (control) version. For example, two new versions of a headline might compete against the original headline.

Multivariate testing, on the other hand, is like running many A/B tests concurrently, where there are multiple elements being tested at the same time.

For example, two alternate product images, plus two alternate headlines, plus two alternate product copy versions create a total of 27 possible combinations (including the original control versions).

Think about using multivariate testing in your mobile marketing strategy for learning how to better influence and persuade visitors to:

? Interact with your mobile brand, content, and functionality
? Adopt mobile site features in order to get information on the go
? Click-through to mobile ads and geo-aware offers, such as coupons
? Register for mobile accounts
? Download digital products such as ringtones, wallpapers and apps

Targeting your mobile audience
Since many organizations have not yet allocated specific budgets for their mobile initiatives, testing a subset of existing, highly-trafficked content on a targeted mobile audience can provide a low-cost and low-risk stepping stone towards building a business case around making a deliberate investment in mobile optimization.

Tests have proven that showing mobile users? content that is specifically tailored for mobile devices improves the user experience, makes the site stickier and, ultimately, increases conversion rates.

With mobile targeting, Web marketers and analysts are able to test, measure and, ultimately, deliver the content, layout and promotional offers that are more effective for each mobile device category.
These can include attributes such as:

? Preferred markup language: HTML vs. WAP/WML
? Keyboard type: physical versus touch screen keyboard
? Screen dimensions and rotation support
? Browser capabilities: scaling, Flash and AJAX support
? Cellular network data speeds: 2.5G, 3G and 4G
? Mobile operating system: Apple iOS, Android, BlackBerry/Research In Motion, Windows Phone Mobile and Palm webOS

Technical constraints ? or not?
While marketers can easily test what is working or not working on their standard Web sites and in their search engine optimization and pay-per-click campaigns, many mobile devices do not support JavaScript-based testing and targeting solutions or accept cookies to track users.

Mobile site operators have estimated these devices to be as high as 50 percent of their audience, thus precluding pervasive JavaScript-based testing, targeting and analytics for these mobile users.

That means you want to look for a non-intrusive mobile testing and targeting platform that does not rely upon JavaScript operations for generating content variations, so you do not have to worry about what browser, version or settings your users have.

That way, you can test, target and analyze users who have disabled JavaScript or cookies, have browsers that do not support cookies, or have chosen to only accept temporary session-based cookies.

Once you have chosen the right optimization platform, you are ready to get started on the path to improving your site for mobile users.

With relatively little in the way of best practices for the nascent mobile medium, it can be difficult to know beforehand which content, user interface element, or aesthetic will be most effective with your audience.

That is why it is critical that you test your mobile offerings before launching them so you can discover which content your users prefer on their mobile devices.

Discover what works by testing elements such as navigation, image size, image choice, specific words or phrases, placement, design, graphical elements, headlines, colors, variations in functionality, or dynamic content.

WHAT IS IMPORTANT to understand about mobile optimization is that it not only shows you which combination of elements your visitors prefer, but it reveals which individual elements influence visitor behavior versus those that do not.

For example, did variations in the product image influence visitor behavior more, less or the same as the copy?

Understanding how each mobile site element influences the visitor experience is the essence of a test-learn-repeat process that marketers can use to prove or disprove the effectiveness of new ideas and continually improve their mobile site's ability to achieve ? and exceed ? their marketing goals.

Kim Ann King is chief marketing officer of Web and mobile optimization firm SiteSpect Inc., Boston. Reach her at .