Monday assorted links by Tyler Cowen May 12, 2014 at 12:36 pm in 1. Why do firms buy ads? 2. Social spiders. 3. Drones watch birds. 4. The behavioral economics of unemployment and obesity. 5. 23andme seems to be moving abroad. 6. Website with the best lectures on health care policy, you can help fund them here. 7. Shirley, can the U.S. compel other countries to cut their carbon emissions?