I'm kinda just pulling this out of the swamp of 25-year-old web design knowledge, but the unclosed code on that page consists of <font> tags, which are long since deprecated, and those font tags have size="2" / size="-2" attributes. I'm pretty sure the old behaviour was that <font size="[signed int]"> affected the size <i>relative to the parent</i> in the same way that CSS "font-size:200%;" or "font-size:50%;" would do. So nesting them doesn't create any new block elements, but it modifies the font size within a <td> or <p> relative to the parent. Just at a look, that seems like the explanation for the increase in font size, in this admittedly odd document.<p>[edit] I believe the page would look <i>as intended</i> if each <font> tag overrode the prior unclosed <font> tag, rather than treating it as a parent, and that was probably how IE 6 interpreted it. In fact I think old browsers would auto-close </font> if you wrote a new <font>.