What is a cooperative?

IMPACT 101: Cooperatives are big business: more than 1bn people are members of a cooperative, and the world's largest 300 cooperatives and mutuals turn over more than US$2tn. But how do these entities work, and what are their benefits and drawbacks? What should you look out for during this year's International Year of Cooperatives? Jeroen Douglas of the International Cooperative Alliance has the answers.