After a truly amazing response to the Knight Lab’s Poop MOOC that was offered last fall (19,000 students signed up!), we have decided to offer this course again in On Demand format, which allows more flexibility for those who sign up for the course. Students will be able to access the course from May-December 31, 2015. This is great news for microbiome research in general-including the built environment-as the more we increase public knowledge and awareness of the microbiome and the myriad ways it affects our health, the more enthusiasm and attention our work will receive. Please share this with anyone who may be interested-friends, family, even enemies-and tell them to sign up today!