Social media can be a key driver of traffic to a retailer’s web site—which means retailers should help spur conversations—says former Walmart.com executive Cathy Halligan, now senior vice president of sales and marketing at PowerReviews Inc., which sells rating and reviews technology to online retailers.

“There’s a simple formula that revenue equals traffic multiplied by conversion rate multiplied by average order value,” she says. “That means that if retailers can increase their referral traffic from Facebook, they can pull a primary lever for commerce.”

Increasing engagement and, in turn, traffic is why PowerReviews added a new application in time for the holidays. The tool lets retailers import onto their e-commerce sites information from Facebook profiles of customers that write online product reviews and agree to share Facebook profile information such as their gender and age. The new PowerReviews feature then includes that information about the reviewer into their reviews and reviewer profiles on e-commerce sites.

The uptake? More retailers adopted the social media integration than the vendor’s question-and-answer tool. That’s because 81% of consumers use reviews to help make their online purchase decisions, she says.

“Consumers are actively engaging on Facebook and retailers understand that,” says Halligan. “In the past retailers were trying to build communities on their own sites. But those communities have had mixed results—engagement is either flat or declining—while Facebook keeps growing. With this tool Facebook can play a role in a retailers’ community-building efforts.”

However, Halligan says retailers can’t afford to rely solely on posting tools to boost engagement. Rather, it should be part of a broader strategy that includes the integration of other features, such as Facebook’s Like button, into their site.

“The Like button is a big generator of engagement,” she says. “If retailers have the Like button associated with products on your site, when a consumer clicks the button it’s shared on her Facebook stream. That gives retailers an opportunity for traffic.”Even though the Like button can be deemed a simplified positive review, Halligan doesn’t think it challenges PowerReviews’ offering. “It’s a complement to the reviews we offer,” she says. “They’re different forms of content. The more forms of content you offer, the more likely you are to drive traffic back to your site.”