A bit of a trick question: If you had $100 to spend, would you be better off devoting that money to doubling the traffic to your site?

Or doubling your conversion rate?

Many marketers get this wrong.

Despite years of front-line, real-world experience to the contrary, more and more online marketing budgets are disproportionately aimed at driving traffic, rather than conversions.

There’s the notion that things like SEO, PPC, affiliate marketing and the like are far more important than increasing shopping cart sizes, decreasing abandonment, upselling and cross selling.

To be sure, driving traffic is a critical mission for any e-commerce site.  After all, no visitors, no sales.

But at the same time, even the most brilliant SEO or affiliate strategies will be for naught if the site itself fails to entice customers to actually buy.

That’s precisely where site testing, optimization, and personalization come in.  Failing to actually sell goods on the site can cost brands the effort, the dollars, and the brand equity that they devoted to attracting all that traffic.

Doubling your conversions can be dramatically more profitable than merely doubling your visitor numbers. And here’s why:

You want insight, not just raw numbers

Slice and dice your site traffic analytics all you want. But at the end of the day, they are still just numbers. What rings the cash register is actionable solutions you can use to improve your customer experience.

The first step is to employ an internal test-and-learn methodology to understand what visitors to your site are engaging with, where they’re dropping off, where their gravitating towards. (Hint: this may even differ by traffic source!)

But only through continuous A/B and multivariate testing, can you actually begin to understand your visitors and place content decisions in their hands. You can fundamentally change how your organization learns about its online traffic. In other words, nobody should be increasing traffic or making a site without a focus on improving conversions.

You want sales, not just visitors.

Yes, going to your boss and detailing how you doubled site traffic in the last quarter is a grand accomplishment! But can you really document how that increased traffic contributed to sales? Do you really know?

If you aren’t tracking conversion rates, or attempting to optimize the site in any way, boosting traffic rates is simply doesn’t matter.

Once visitors land on your site, your goal is to get them to buy (and hopefully become repeat customers). This is where testing and personalization are essential to turning traffic into sales.

Optimizing your site for content, design, offers, and copy is the only way to ensure your are taking full advantage of your site traffic. If the experience is irrelevant, frustrating or cumbersome, you might as well have not ever invited them to your site in the first place.

Better experience, more dollars

Today’s consumers are good at comparison shopping. They research, they sign up for emails, they track down deals.  Which may lead you to believe that the key is to boost your traffic as much as possible.

But the reality is, if you provide a really stellar online experience, they will want to come back, again and again. Which makes the overall job simpler, and clearer.

Thanks in part to more advanced testing methods, it’s a lot easier to listen to what your visitors want (and need).  Customers have become a lot more vocal even if they don’t know it. Through their clicks, page views, bounces, reviews and purchases, your online customers offer real-world feedback about their online experiences, in real-time. So pay attention to them. Make website changes and marketing decisions based on your customers, not on what your gut — or marketing budget — is telling you to.

Personalizing wins

Getting into a traffic war with your competitors is a sure-fire way to waste resources and precious attention.  It’s far more effective step up your game by using testing and conversion optimization to gather data and visitor profiles that can dramatically increase actual sales and repeat visits.  You may even find that segmenting your customers by where they came from can help you convert them into loyal and repeat buyers.

When it comes to their websites, major e-commerce players need to realize that only through a customized combination of multivariate testing, optimization and personalization best practices can they truly begin to tailor experiences in meaningful and profitable ways. It’s an ever-evolving practice that reaches miles beyond SEO, ad targeting and landing page optimization. But the rewards of it means a lot more return traffic, and a lot more improved conversions.

Follow the money

No matter how you define a conversion, at the end of the day, the holy grail for e-commerce marketers is to increase site sales. And the dollars are in the details, not just the volume. Focusing on conversion rates is where you’ll see not only site engagement improve, but revenue as well. Your traffic drivers might bring you more people, but conversion strategies bring you more money. No contest.

When it comes to site optimization and traffic acquisition, the best brands aren’t just surviving — they’re thriving. By focusing on the deep analytics and insights gained from testing with online customers, not just boosting traffic, not only improves the efficiency and effectiveness of their e-commerce site, but several other aspects of their businesses as well. They have a better grasp on who their customers are, how they buy, when they buy and what they buy.

In short, they can offer experiences more suited to customer needs and wants — and that is the true goal of any e-commerce business.