I was poking around this website and I noticed that I didn’t have the correct MIME types set up for my RSS or for the RDF that is scattered around. I have link tags in my HTML head section that point to my RSS file:
<link rel="alternate" type="application/rss+xml" title="RSS" href="http://InternetAlchemy.org/index.rss" />
The type attribute on the link tag says that the content pointed to by this link should be of type application/rss+xml, which it wasn’t!
To help diagnose these kind of problems I wrote a short CGI script that fetches a page and parses it to detect <link>, <script> and <object> tags, fetch the content pointed to by the tag and compares its mime type with that specified in the type attribute.