This entry was published at least two years ago (originally posted on September 3, 2002). Since that time the information may have become outdated or my beliefs may have changed (in general, assume a more open and liberal current viewpoint). A fuller disclaimer is available.
One of the stumbling blocks I discovered today about enabling Trackback is that it breaks the W3C Validator — even though I make sure to use valid XHTML 1.0 in my pages, the validator chokes on the RDF code needed for Trackback to work correctly.
Luckily enough, this evening I stumbled across a discussion of this very problem on philringnalda.com. Brad was kind enough to post a (theoretically) simple PHP trick to hide the RDF code from the validator — unfortunately, for some reason it’s just not working for me. Harrumph. Guess I’ll just go with hiding the RDF data inside HTML comment tags for the moment — it’s a little kludgy, but it should work until something better comes along.
End result — the validator likes me again.