Their new business model is more complicated than their previous business model. The five steps to citizenship seems like a weird concept. People that want to host a Q&A site like these don't want to be told they aren't good enough to have a top-level domain. Imagine wanting a blog and WordPress or Tumblr thought you undeserving of a top-level domain. Stack Exchange 2.0 has more steps to have a top-level domain site than the Chinese government has for it's citizens to acquire a domain. I'm sure there is a good Rails/PHP Q&A clone webapp.