The idea is deliciously cool: Ben & Jerry's Twitter application takes the unused characters in a standard 140 character tweet, left hanging as dead, white air space, and creates a "fair tweet" message with a link to information about World Fair Trade Day.

Visitors to the site, created by Amalgamated and Stink Digital, sign up to become Fair Trade supporters, and automatic messages immediately begin appending themselves to that person's tweets.

Recently, Ben and Jerry pledged to produce ice cream with 100% fair trade ingredients. There is a huge market for Fair Trade goods, worth about $1.3 billion, and growing +43% yearly, according to TIME.

"Fair trade is about making sure people get their fair share of the pie. The whole concept of fair trade goes to the heart of our values and sense of right and wrong. Nobody wants to buy something that was made by exploiting somebody else," states Greenfield.

We’ve loved them – and their ice cream, since 1978, when the lifer friends opened their first parlor in a renovated gas station in Burlington, Vermont, having completed a $5 ice cream making correspondence course from Penn State’s Creamery.

Greenfield and Cohen built their Pop & Pop brand into a beacon of social activism while concocting outrageous desserts such as customer-inspired Cherry Garcia, Chunky Monkey, and Chubby Hubby. Stephen Colbert, John Lennon, and Monty Python are three of their celebrity-inspired pints, and they renamed their butter pecan flavor to "Yes Pecan!" after Barack Obama’s presidential win.

In 1988, one decade in, they established the non-profit "1% For Peace," with a goal to redirect one percent of the national defense budget to peace-promoting projects, and they launched their three-fold mission statement: Profit marks only one-third of their company’s activities.

The brand gained fame and as it grew into a multimillion-dollar publicly traded company, became the target of a bidding war, which in 2000, Dutch conglomerate Unilever won with a $326 million bid, but, it took Ben and Jerry out of the day-to-day picture for several years, as they were disenchanted with their new owner’s lack of commitment to the founding mission of corporate social responsibility.

When Walt Freese joined as CEO, he lured Ben and Jerry back with a plan to commit to buy products from farmers who were advocates of sustainable agriculture.

“There was always the commitment on the part of Ben & Jerry’s and Unilever, post-acquisition, to honor the social mission and to do things that are true to the social mission,” said Freese. “What got lost over time, initially, was that Ben and Jerry had not just honored the social mission, they had committed themselves to being leaders, had committed themselves to being activists. Ben & Jerry’s was less courageous for a period of time, post-acquisition.”

Ben and Jerry picked up their original gauntlet and launched a new flavor, American Pie, to persuade consumers to call for changes in national spending priorities: the goal was to shift $13 billion from making and maintaining nuclear bombs into pediatric health insurance, new schools and other programs for kids.

By 2003, their 25th anniversary, they had converted all of their farms to operating on green energy, and begun using only cooperatively-run farmer groups and Fair Trade-certified ingredients for all their products.

“I think that business is the most powerful force in the country,” Cohen said. “When business starts using its voice for the benefit of the country as a whole, not just in its narrow self interest, it can really be the force that can make the changes that need to be made.”

Their 2010 declaration of commitment to Fair Trade was lauded by TransFair USA's President and CEO Paul Rice who starred in this video last year:

World Fair Trade Day 2011’s mission is: “to enable producers to improve their livelihoods and communities through Fair Trade. WFTO will be the global network and advocate for Fair Trade, ensuring producer voices are heard.”

According to their site, 2.7 billion people, more than a third of world’s population live on two dollars a day, and 925 million people worldwide don’t have enough to eat.

"Ben & Jerry's has been using word of mouth marketing to support our social mission programs for decades," said Noelle Pirnie, senior global marketing manager at the company. "Now with social media, we have the tools to amplify our voice like never before. Five years ago for World Fair Trade Day, we may have held a rally in front of 100 or so people, hoping the media would come out. Now we can reach our fans around the world and truly engage them in the conversation to understand that every purchase counts."

This year’s theme: “TRADE FOR PEOPLE – Fair Trade your world.” You can sign their declaration on Facebook.

Ben & Jerry’s, now owned by Unilever, epitomizes the maxim of “doing well by doing good.” They’ve consistently modeled that adding social value to business is…good business.

In a Fair Trade world, “where every purchase matters,” ethical ingredients, an ethos of sustainability and social currency - and delicious ice cream with a sprinkle of humor, make Ben & Jerry’s latest Twitter application a new standard for digital activism.

Tweeting has never been sweeter or more fair.