Like Adam Kessel wrote in a recent blog entry blosxom can't put things into multiple categories. This is unfortunate but true. But from reading the plugin documentation it should be fairly easy to do it with the entries subroutine and symlinks.
I have thought about it myself already for some time. My thought so far was that it needs a main category to which an entry belongs (in which it gets displayed when you have the root feed), and that I will choose the rest on the timestamp of the symlink, if the plain file isn't below the current directory. I guess this is the thing that I needed to actually start writing it. Stay tuned...
mutt is getting annoying. Still isn't able to be used properly as an imap client, and the gpg handling is also far from optimal. (Ever tried with two keys with different passphrase and had to guess which one to use when decrypting a mail? Why isn't mutt able to display which keyid it wants the passphrase for? Or on sending a message when quering which key to sign the mail it displayes all the public keys in the ring...)
So what are the options? For I am not an emacs users gnus is a no-option. I have heard the latest hype about elmo and etpan. While the former is already packaged it has a major drawback: PGP support is only on the wanna-have list, not on the general todo list, so I have no idea when it will be added. So it ruled out itself for the time being, too. etpan on the other hand isn't packaged yet. It has a debian subdirectory in CVS though, but that is aged like hell on the other hand (not a real problem, I would roll my own debian directory anyway). Just found out that there is already an etpan-ng directory in CVS. One thing that gets me interested is that they are planing to add perl binding, which can be really helpful. Lets see.