The SO community is widely criticizing the change, citing problems with the decision-making process that led to it and complications that may arise from mandating attribution. Why did SO make the change in the first place? They say "it's always been a little ambiguous how CC-BY-SA covers code. This has led to uncertainty among conscientious developers as they've struggled to understand what (if anything) the license requires of them when grabbing a few lines of code from a post on Stack Exchange. Uncertainty is a drag on productivity, for you and for us, and we feel obligated to make code use more clear."