QR Codes are cropping up everywhere from print ads to posters to direct mail. In fact, growth among smartphone users is up 700% since the beginning of 2010.

QR Codes entice consumers to scan them on their cell phones to get in on a deal or to get more information.

Early adopters love them because of their cool factor. Marketers love them because they bring consumers to specific websites to create more interest in the product and to get them more involved in the buying process.

But how well do QR Codes actually work?

To find out, a national marketer recently mailed several test packages. The results are in.

As measured by total interactions — calls, clicks and QR scans — more people responded to the QR Code. In fact, people were twice as likely to scan a QR Code and be directed to the mobile site than visit the traditional online site. However, perhaps as a result of this channel preference, call volume was suppressed.

Although QR Codes helped increase interaction with and responsiveness to the product, they did not immediately generate incremental sales. However, these prospects are more sales-ready and more receptive to future messages.

What’s more, adding robust video to a mobile site increased conversion 2-3 times over the benchmark control.

Given their relatively low investment in time and money, QR Codes deliver on their promise. And that’s always hot.