A growing number of quick serves are using the power and influence of social media to revolutionize online ordering.

Facebook now boasts 500 million active users. The average Facebook user clicks the Like button nine times, writes 25 comments, and becomes a fan of two pages each month, according to Mashable’s Facebook Factlook. The average user also has 130 friends on the site—giving their Likes a wide reach of influence among friends.

Realizing the influence Facebook users have on their networks, a growing number of quick-service restaurants are taking their fan pages to new heights by incorporating online ordering directly through the Facebook interface.

“When a customer thinks about ordering food from a restaurant, they need to be able to use whatever platform they might have available at the time,” says Joe Gagnon, CEO of Exit41, an online ordering software provider for the restaurant industry. “That could be online, with a mobile application, via Facebook, walking up to an ordering kiosk, or by calling in. And all of these options should flow through one application.”

Software from online-ordering companies like Exit41 can usually be integrated with a restaurant’s existing point-of-sale system so orders show up as if the order was taken locally.

Geoff Alexander, executive vice president of Lettuce Entertain You Enterprises and managing partner of Wow Bao, an Asian eatery based in Chicago, partners with Exit41 for the restaurant’s online- and mobile-ordering platform. “For us to have online ordering directly from our Facebook page is forward thinking, and I think that’s where the Internet is moving to.”

Alexander says Wow Bao had to find creative ways to use a limited marketing budget, and social media provided an alternative to traditional and costly marketing methods. The team at Exit41 presented Alexander with the idea of focusing the restaurant’s marketing efforts and budget on a Facebook page with online-ordering capabilities and a mobile application that allows customers to place orders via their iPhones.

To keep customers engaged and placing online orders, Alexander says he posts frequently to the Facebook and Twitter accounts. “Every Wednesday on Facebook we post a secret word, and if customers say the secret word [when ordering], we give them something for free. We’ve been doing that for a year or so.”

Another key way quick serves can take advantage of Facebook is by allowing customers to link their personal Facebook accounts directly with online ordering software—making it even easier to place orders and share online activities with their friends. NetWaiter is one online-marketing and ordering provider for restaurants that offers websites that quick serves can customize with their own branding and menu. A NetWaiter site can link to an existing site or to an e-mail address, fax machine, or POS system.

“When a customer places an order through a restaurant that uses NetWaiter, and they use their Facebook account to log in, NetWaiter will take the restaurant’s logo and post it to the customer’s Facebook feed that says, ‘John Doe just placed an order at Joe’s Tacos,’” says Jared Shimoff, senior director at NetWaiter. “That post links back to the NetWaiter site for Joe’s Tacos. So it’s a neat way for customers to tell their friends, ‘Hey, I just ordered here.’”

Shimoff says that, depending on the restaurant, up to 50 percent of customers will permit NetWaiter to post the activity to their Facebook wall for their friends to see.

While social media often presents a challenge to businesses trying to evaluate the return on investment, online-ordering applications can offer more concrete results.

“People keep asking me how we measure ROI on social media,” Alexander says. “I base it on three things: Are we having fun? Yes. Are sales up? Yes. And are we being talked about? Yes. Since the Facebook launch with online ordering, our sales have grown about 10 percent in five weeks.”

With all of the buzz and urgency surrounding social media and mobile apps, jumping head first into an online-ordering application on social media might seem like a logical next step for any quick serve. But Alexander says operators must take it slow.

“There are so many different [tools] out there for social media. I would say pick one and do it well,” Alexander says. “It’s a commitment. We didn’t just flip a switch and go with everything. Each component came one after the other as we grew and evolved. It’s better to go slow and get it right than to put up something you’re constantly changing. When you make changes, you have to turn it off, and that’s causing you to lose customers.”

Of course, there are several tools in the social media world that can serve as a launch pad. Alexander chose to start with Twitter and Facebook pages and grew Wow Bao’s following in that space. Then he slowly added applications like the Facebook and iPhone ordering functionalities.

Like traditional websites, social media and mobile-ordering platforms require marketing to boost awareness, traffic, and ultimately sales. NetWaiter provides operators a manual with tips for best practices, how to promote online ordering to their customers, and how to make it easy from an operational standpoint.

Shimoff says that to market online and mobile ordering to customers, operators need to create awareness for their customers. “Every time someone calls, take their order, of course, but let them know they can place their order online and tell them to check out your site,” he says.

At Wow Bao, Alexander uses in-store signage and table tents to promote the restaurant’s social media pages. He also markets the mobile-ordering platforms to his existing Facebook, Twitter, and e-mail contacts.

Online ordering through social media, he says, will continue to grow as more consumers learn about it.

“It’s not going away, that’s for sure,” Shimoff says. “It’s a logical step for customer convenience and the marketing for the restaurant.”