Evan Schuman's StorefrontBacktalk

That delicate mobile-commerce balance between apps and the mobile Web became a little clearer on Monday (March 12), when a new Nielsen study found that almost 60 percent of smartphone users connected with the top five E-tailers during the peak holiday selling season, and the mobile Web was twice as popular as apps. But most of those customers used either apps or the mobile Web—not both.

It’s more evidence that customers use apps and the mobile Web differently. And if you don’t leverage that difference, you could lose a sizable portion of your M-Commerce customers.

The Nielsen survey, which involved metering the smartphones of 5,000 volunteers, tracked whether those participants connected with Amazon, eBay, Wal-Mart, Best Buy and Target. Not surprisingly, both app and mobile Web use went up in November, peaked in December at 59 percent, and then fell back in January to 52 percent.

The mobile Web was used by about twice as many people as apps for connecting with E-tailers, which caused Nielsen’s analysts to declare that smartphone owners “prefer retailers’ mobile Web sites over mobile apps.”

But the reality is more complicated, according to Nielsen’s numbers. About 7 or 8 percent of smartphone users are die-hard app users—they apparently don’t use the mobile Web at all. Another roughly 30 percent only use the mobile Web. Only about 18 percent use both apps and the Web.

That suggests E-tailers still haven’t figured out that apps and mobile Web sites should let customers do different things. An app shouldn’t just package the Web site experience in a box—what’s the point of that? It should be designed to do something well that the mobile Web site can’t do as well—or can’t do at all.

Some big E-tailers seem to have backed into that without realizing it. Amazon’s iPhone app, for example, is fine for making purchases, but only if a customer knows exactly what he wants to buy. But when it’s time to search for a product, that’s easier to do in a mobile Web browser.

That explains why a customer might use both apps and the Web. But why so many Web-only users? One reason is that the Web comes free—no iTunes, no downloads, no complications (at least as long as the mobile site renders correctly on the mobile browser). That means a single site (with the obligatory tweaks for each major browser) can reach virtually all mobile users.

Another reason: Sites are inevitably easier to upgrade than apps.