Teaching with blogs

I am requiring my Ph.d. macro class to read some blogs, and yes there will be a test.  They are to read Brad DeLong, Brad Setser, Macroblog, Nouriel Roubini, and some of Econbrowser, all to be found on the blogroll to the left.  I am a proponent of debate as a means of educating; we are programmed to remember interpersonal exchanges better than written or spoken drones.