Paul Krugman, a professor of economics at the University, is also a writer for The New York Times. This semester he is teaching WWS 543: International Trade Policy and has apparently decided to make some of the course's content open to the general public.
This semester, he has been posting content from the class on his blog, The Conscience of a Liberal. This week, he is apparently lecturing about preindustrial trade. Surprisingly, none of the commenters have remarked on this unusual blogging activity.