Everyone loves an underdog – especially in hard times. So it’s good news to know that in this brutal market sales of Fairtrade products rose 12% year-on-year, to £800 million. Part of that success at least can be narrowed down to the do-gooder organization’s anything-but-charitable use of social media.To be sure, sales of £800 million is still a fraction when compared to major brands, but noteworthy nonetheless for an organization with relatively scant financial resources.

The Fairtrade Foundation, which is holding a Fairtrade Fortnight in London beginning today, attributes the growth to brand loyalty, even though 2009, as it notes, was “a desperate year” for many of its suppliers. The plight of its suppliers has been a recurring theme on its YouTube channel and Flickr feed.

Indeed, social media plays a big part in Fairtrade’s winning strategy. With a Facebook page connected to more than 30,000 fans and a Twitter feed that goes to almost 5,000 followers, it’s been adroitly publicizing events like the Fairtrade Fortnight and directing people to related causes.

The structure of the organization plays a role, too. Grassroots activism has social networking coded into its DNA. And for years the Fairtrade movement has been working like a vast social network  well before the advent of Facebook. For example, in 2002 it created FLO,  Fairtrade Labelling Organizations International, which allowed for a literal grassroots net to gather and join with discrete organizations by introducing an international labeling standard. This movement continues to thrive today.

All this may just be a perfect model for means-stretched activist organizations that need to spread a simple message forcefully without ramming it down people’s throats. And the 12% increase in sales is proof it’s working.