The companies making the most efficient use of Twitter.

If there was going to be a Facebook 50, there had to be a Twitter 12. After all, 2009 has been Twitter’s year. Traffic has quadrupled, investors have recommitted, the media has fawned. Even if Twitter isn’t the future of social media, it’s certainly the shiniest, newest thing flitting in front of us. And businesses love shiny new things.

Thus, this year has also seen corporate America come into its own on Twitter. Some use it for customer service, others for exclusive coupons, and still others to pump out RSS feeds of in-house events. In Twitter, PR departments have found a two-way loudspeaker: an unfiltered way to reach a company’s fans and a Big Brother opportunity to keep tabs on its detractors. As an entire social media platform devoted to self-marketing, it’s surprising Twitter isn’t funded by the Chamber of Commerce.

But just because a ton of businesses are using Twitter doesn’t mean they’re using it well. The Big Money set out to figure out which companies sit on top of the Twitter heap. The overarching question: Which companies get the most out of Twitter? To figure out the answer, we took a mix of the salient metrics: number of followers, growth from September through November, number of tweets, and whether the account is doing anything besides providing a transplanted RSS feed. We only included companies with follower counts higher than a million. (There were other stipulations—for instance, the feed needed to represent the company, not the CEO of the company, and the business couldn’t be a derivative of Twitter.) The assumption was that a company with 100,000 followers couldn’t be getting more out of Twitter than the one with a million. That left us with 32 companies. With the help of Twitterholic, a site that tracks Twitter accounts’ metrics, we aggregated the sites’ stats and created a weighted rubric by which to judge.

After much number crunching we ranked our top 12. You can see the final list by clicking here.

The list is far different from TBM’s Facebook 50, with only two entrants making both lists (the NBA and CNN). It’s a telling split, and evidence that Facebook and Twitter serve different purposes for different customers, whether they be companies or consumers. Below are some trends we noticed while putting together the Twitter 12:

• The disproportional influence of the “Suggested User” List: In March, Twitter announced it was going to start suggesting accounts for new Twitterers to follow. “When you don't follow any other accounts on Twitter the product is not as relevant as it could be,”  cofounder Biz Stone wrote on Twitter’s blog. The list has over 400 accounts on it, and all but one of the corporate accounts that cleared the million-follower threshold were on the list. (As of press time, CNN Breaking News is the only exception.) Twitter has given a handout to some but not all, creating a schism in their community of users. Why does @jetblue get recommended and @comcastcares doesn’t? They’re both customer service accounts for a huge national company. And yet @jetblue has 1.5 million followers and @comcastcares only has 35,000. Because of the Suggested User List, @comcastcares never stood a chance at making the Twitter 12. Twitter declined to comment on whether there was a methodology to the list, but did say that one of its priorities moving forward is finding a better way of recommending users.

• Customer service happens on Twitter in a way it doesn’t on Facebook: Many companies run their feeds like an emergency hotline. Tweets like this one on one of Dell’s feeds are common: “@kristiewells Hi Kristie. Anything I can help with?” This is the kind of question that a customer service rep would have asked by phone. But the tweets are far more powerful. In @kristiewells’ case, Dell is reaching out to her, implying that her concerns are important. The normal customer service dialogue has been changed; it’s now asynchronous and public. Dell could’ve ignored @kristiewells, but it chose not to. And it chose to tell the whole world that it was trying to help.