Underappreciated XHTML Tags

There are a lot of XHTML tags that just aren’t appreciated as well as they should be. <a> gets all the love, and now that we’re all on standards compliance kicks we can’t get enough of <div> and <span>. But what about the other tags? No one likes <blink> (deservedly so) but the opposite of love isn’t hate, it’s indifference.
There are tags that just don’t get the press that they deserve. I’d like to present some of the best tags that you’ve never heard of.

<dl>, <dt> and <dd>

<dl> stands for definition list; this tag list is a definition list. Unlike <ul> and <ol> it has two paired list items:
<dt>: definition term
<dd>: definition definition (no typo)
I like this because it’s hella semantic. The <dd> defines the <dt>, semantically it’s like a hash in Perl.

<del> and <ins>

<del> is more often than not used for comedy. It’s an update of the old ^H^H^H joke, wherein the typist would pretend that they thought they had deleted something. Example:

Old:
David can suck it^H^H^H^H^H^H^H^H^H^H^H^H is a great guy.
New:
David can suck it is a great guy.

Well I just sucked the humor out of this post. But <del> and its lesser known sibling <ins> are becoming more and more useful. As we update our weblogs, we usually throw caution to the wind – ignoring spelling, grammar and even consciousness. Then, as we sober up, we go back and edit our posts to be meaningful gems that light up the Intarweb. But without highlighting the changes, posts saying "WTF? Is that even Englilsh?" don’t make much sense when attached to you now literary masterpiece.
In order for there to be some semblance of cohesion on the web, it’s important to use these preferably styled tags. Take a look at Stephen’s comment – Stephen would look like an idiot if I had just made the edits. You don’t want to make Stephen look like an idiot, do you? Also, it’s hella semantic

<acronym> and <abbr>

The <acronym> tag is surprisingly used for defining acronyms, <abbr> is for abbreviations. Both tags have a title element to define what they are shortening. The difference between an acronym and an abbreviation is that you can pronounce an acronym. WYSIWYG is an acronym because you can say "whizzy-wig" but HTTP is an abbreviation. I’m a fan of these tags because they’re hella pedantic.

So why do semantic tags matter? They are the starting point for the semantic web, which allows computers to parse meaning from the text on the web. Your weblog posts can contribute to a global information store today, by using tags that describe the content inside. For a glimpse of the future, check out the new Harpers’s Magazine site (via Brian), which uses semantic markup to build a database on everything from Satan to Kentucky. Cool, huh?
So what are some other cool tags that aren’t used enough?