On the Cast and Crew subpage is listed my Melanie Bush page, and on the Organisations subpage is listed the NZDWFC site. Neither of them have a page rank listed and so are at the bottom of the list.
I emailed Google a while back to ask why this is so, and got a response saying the situation would correct itself over time and I didn't need to do anything. So far, it hasn't.
I don't know why Google's presumibly-automatic URL matching software doesn't recognise that the pages are ranked. What's equally weird is that the Google toolbar correctly lights up the "Category" button for my main DW page and the Mel Bush page, but not the NZDWFC page.
Addendum: I just remembered The DiscContinuity Guide was added to dmoz.org's Episode Guides page in December, but has yet to show up on the same page in Google's directory. Google's directory is basically a mirror of dmoz.org. I guess Google haven't updated their mirror in the last three months.