Just realized that I've never seen a Math ping list on FR.
Just realized that I've never seen a NakedMathWithFeathers ping list on FR.
While we have a number of people who are interested in mathematics, I believe that most of the math-related threads on Free Republic tend to be about math education. (Though I do remember a longish one about equations back in October: What Makes an Equation Beautiful?)
Looking at threads with the key word "math" (http://www.freerepublic.com/focus/keyword?k=math), I would not surmise that such a ping list would be a "high volume" ping list.