I don’t know whether this has been fixed in Movable Type 3.1 (I’m on the beta test list but haven’t really had chance to play around with it) but the
<MTCommentAuthorIdentity> tag outputs invalid HTML. It’s used to display a TypeKey commenter image with a link to that person’s TK profile if that person used TK to post a comment.
The offending code is in the image tag, where the image is given an illegal
valign="middle" and isn’t terminated in the proper XML way, thus making it valid in all forms of XHTML. It also includes a
border="0" attribute which would make it invalid XHTML 1.0 Strict and above. Consequently, any article where a TK user has commented becomes invalid 🙁 .
incidentally, I’ve made a couple of changes which, fingers crossed, will mean that all comments are posted in Unicode, and so any ‘funny characters’ that are posted shouldn’t ruin the validity of the page. That’s the theory anyway.