I am not sure how this happened but your reply is missing several closing tags. As a result, the page content below your reply is not displayed/functioning properly. If you can, I suggest you fix it. If not, then perhaps you could ask an admin or VSTF member.
Yeah, I posted this before I got to the other thread where Tupka217 (I think) already told you about it. I have trouble imagining that HTML3 would have been this different though. I mean, that would have been a pretty significant syntax change.
I am not sure if you know this or not, but you don't have to use HTML in your page content. MediaWiki actually uses wikitext, not HTML. It takes what you have given it in wikitext and converts that into HTML. For instance, instead of using ul and li tags to create a list, you can use MediaWiki's list syntax.
For convenience, wikitext supports some HTML but there are also some HTML tags that are not supported; mostly for security reasons. You can find a list of allowed HTML tags here.