Wordpress category hider plugin
OK, it was so easy to write a plugin as opposed to doing other things that I went ahead and made a plugin to do it.
My category hider plugin allows you to make posts in a selected category (or more than one) display a stub text on the main page of your blog and in your rss feeds. The post still displays in full in your archive pages (but only for the selected category) and on its own page. Of course, tweaking where it gets hidden is trivial.
If you want the category’s posts to be completely absent on the page or in the feed, I doubt a plugin would allow you to do this. If it is possible, it would be a very different plugin. (If you know PHP, on the other hand, the hack is pretty straightforward.)
I’m not going to bother providing a download right now. If you’re interested, comment, and I’ll see about getting together a download for it.