Here’s an alarmist prediction: 2010 will see the mainstreaming of social media as a marketing tool for big business. As I type, brand managers and creative directors the world over are salivating over the viral buzz social media will deliver.

Buzz is all well and good. But I can’t help but fear that the rush to use Facebook, YouTube, Twitter, et al, as the “killer” new marketing channel will trample over one of the very principles of “social”: that transparent conversations can create a better relationship between customers and companies.

It was in this slightly gloomy frame of mind that I decided to explore whether social media marketing campaigns can really claim to be social.

A partial answer can be found behind the scenes at Fiesta Movement, Ford‘s  recently concluded six-month social media experiment in which it put a new Fiesta car in the hands of 100 “agents” (members of the public) to drive and review using Twitter, Flickr, YouTube, and blogs. (A note of disclosure: Custom Communication has worked in Europe with Volkswagen on social media thinking and community engagement.)

Fiesta Movement, most social media commentators agree, was a huge success. The 700 videos produced by the agents have generated 6.5 million views on YouTube, and there have been more than 3.4 million impressions of Fiesta Movement on Twitter. Even photos taken by the agents have been viewed more than 670,000 times. When it comes to word-of-mouth marketing, those are serious numbers but—and this is a big but—they are just numbers. If, as a company, you care only about looking good judged by Facebook fans, YouTube views, and Twitter followers, then surely you are missing the social part of social media. What has Fiesta Movement actually done for Ford’s relationship with its customer and potential customer base?

“Social media is not a selling tool; it is a relationship tool for us,” Jim Farley, Ford’s Chief Communication Officer, explains in an e-mail exchange. He notes that Ford looks to evaluate social media interactions in a different way than it would TV or digital marketing.

As Scott Monty, Ford’s head of social media, told me, while creating buzz from Fiesta Movement was certainly important (more than 50,000 U.S. consumers who interacted with the movement said they wanted more information about the vehicle, and 97 percent of those do not own Ford vehicles), equally important was the customer feedback on design and engineering issues that the Fiesta agents have delivered. This was particularly important given that Ford will be introducing this version of the Fiesta—a European car—into the U.S. market for the first time.

The principle of applying social media lessons across the company is not new to Ford. Farley decided back in 2008 to implement a companywide social media strategy. That’s when he hired a socially savvy outsider—Monty—to build relationships with social communities. The automaker also decided that its social lessons wouldn’t stop at the door of PR or marketing. Much like the feedback it has solicited from the Fiesta Movement, Ford has picked up similar insights from syncmyride.com—an owner-to-owner forum that quickly compiled a series of complaints about the voice on Ford’s SYNC hands-free in-car connectivity system. Based on that feedback, Ford engineers tweaked the software to turn down the volume, recounts Monty.

Ford’s intention is to consider how social media can inform the company as a whole, rather than judging its efforts by the criteria of one department and those “holistic” lessons filter up and down through the company, says Monty. That includes the company’s executive board and goes as far as putting up senior execs for online Q&As through Twitter and on the corporate Facebook page. “There is a healthy respect for [social media] and how we participate in it. Two-way dialogue is healthy for a company like Ford, and we’ve grown as a result of having participated in it,” says Farley. At some point, as executives grow in seniority, they tend to become “isolated from reality,” adds Monty. Making the Ford board aware of and engaged with social conversations counters that isolation. “When [CEO Alan Mulally] says we are making the cars people want, well, how do we know unless we are listening?” asks Monty.

Of course, as Big Three competitor GM can attest, social media listening and conversing can be a tricky business, especially when it comes to thorny automobile industry issues like jobs and sustainability. In the past, Ford itself has experienced infamous bumps in the road over product safety—reputation problems that lingered for a long time even in the offline world. Given the precarious health of the automobile industry along with the intensity of brand passion and criticism expressed by the automotive social media community, it’s no surprise that Ford has made engaging online communities a priority.

Now with the recent launch of the new Focus and its one-world car platform, Monty and Co. must prepare for a truly global conversation and the challenges that will bring. What Ford learns will be relevant for the whole company, not simply the marketing and communications teams.