I am subscriber of the Test Driven Development mailing list as well as the RSpec ones. One thing that strikes me continually is the lack of innovation and new ideas in the former one, as opposed to the flurry of brilliant ideas constantly coming out of the RSpec one. It seems to me that communities stagnate and that the people who once were the revolutionaries turn into keepers of their own revolutions ideas. The free thinkers become conservative.
Guy Kawasaki gave a brilliant keynote on the MySQL conference, talking about innovation. He said that the only way most people think about how to improve themselves is by using the tools they know more proficiently. No makers of horse carriages became car manufacturers. And the original TDD’ers are still talking about the same things they did five years ago. The revolution has moved on.