The article offers many other points of interest. For instance:
By guaranteeing a minimum price, Fairtrade also encourages market oversupply, which depresses global commodity prices. This locks Fairtrade farmers into greater Fairtrade dependency and further impoverishes farmers outside the Fairtrade umbrella. Economist Tyler Cowen describes this as the “parallel exploitation coffee sector”.
Coffee farms must not be more than 12 acres in size and they are not allowed to employ any full-time workers. This means that during harvest season migrant workers must be employed on short-term contracts. These rural poor are therefore expressly excluded from the stability of long-term employment by Fairtrade rules.
In other words, it's mostly a marketing gimmick.
via Marginal Revolution: Facts about FairTrade.
tsk tsk for starbucks, et al!