FeedBurner, which powers hundreds of thousands of blog, podcast and mainstream news feeds (including this one), is apparently being blocked by Chinese authorities. Here is a Yoda-esque loose English language translation of William Long's original post. William even used a proxy server to verify that the issue is with the Chinese, not FeedBurner. His subscriber count dropped from over a thousand readers to zero overnight.
Sometimes a feed can remain visible during a blockade if it using a third-party RSS tool like Feedburner. However, if censoring countries are going to start blocking Feedburner as well as blogging tools like Typead and Blogger.com then the third-party tool won't be any help. Government's can block a domain like Blogspot.com, Typepad.com or Feedburner.com which results in a block of all the blogs and feeds using that domain. We recently witnessed this during India's blog block following the Mumbai bombings on 7-11 when typepad.com, blogspot.com and geocities URLs were blocked.
A couple comments on Steve Rubel's post suggest that the blocking may have been a temporary glitch and not necessarily an intentional censorship move by the Chinese government.