Put there by some html editor. Never heard of a SE that would even look at such tags. Only non-standard tags that I've heard are looked at, are Front page author tags so that Excite and Inktomi can properly handle the non-standard html.
Interesting, I never knew they were being adapted by any SE's. It would be nice if they were to do so state side. One of these days, I'm going to have to find time to educate myself about the Euro engines - sure is a different game over there.
Until then, we will continue to disect Fantomasters brain.