McDonald's, Home Depot, Nike -- these are not the clients of your typical environmental do-gooder. But for Jill Rosenblum, communications and outreach director for the U.S. office of The Natural Step, working with these and other corporations is par for the course. As an international research and advisory organization, The Natural Step works with big business, governments, scientists, and academics to encourage sustainability. How? By making people think about their choices, and offering up different ones. For instance, what kind of coffee you buy makes a difference -- and it REALLY makes a difference if, say, you happen to be in charge of purchasing beverages for McDonald's. As this week's diarist, Rosenblum chronicles her efforts to help people, companies, and countries make sustainable choices -- only on the Grist Magazine website.