Stuff still needing to be done with tags:

* It's unfortunate that the rss category (tag) support doesn't include
  a domain="" attribute in the category elements. That would let readers
  know how to follow back to the tag page in the wiki. However, the domain
  attribute is specified to be the base url, to which the category is just
  appended. So there's no way to add ".html", so the url won't be right.

  This is one good argument for changing ikiwiki so that pages are all
  dir/index.html, then a link to just "dir" works.

  So this could be implemented now for userdirs wikis..
