Summary:

<address>, <q>, <optgroup>, <acronym> or <abbr>, <fieldset> and <legend>

This article is quite old. You'll find more recent use cases/examples on the current HTML5 editor's draft (http://dev.w3.org/html5/spec/Overview.html). In its temporal context the author was right (fieldset/legend/abbr weren't that used) but fortunately times have changed a bit and things aren't as bad as he describes.

I must be one of the luck SOBs who learned proper HTML and web development first, having picked up this whole web fad just in the last year (took a long hiatus, my last web app before that was written in 2003.) I have html-generating macros and I use legend, label and abbr within fieldsets throughout my code base (though I usually forget they even exist until I see the generated code.)

Hate to be a jerk, but I really don't see what <address> adds over <div class="address">

It is was an actual microformat for addresses, that makes sense, but it's not. It's just a tag that implies that some kind of address (virtual, physical, who knows) is contained within. Who does this actually benefit?

<address> doesn't mean what you think it means:

http://www.w3.org/TR/html401/struct/global.html#edef-ADDRESS

"The ADDRESS element may be used by authors to supply contact information for a document or a major part of a document such as a form. This element often appears at the beginning or end of a document."

Fair enough, but what does that add?

We should use the tag so that some yet-to-be-invented web spider might be able to automatically extract contact info for the pages it crawls?

<address> is what people should have been using all along - I remember it was common in academic websites in the early-mid 90s, but it fell out of fashion. Similarly <em> for emphasis, the semantic meaning was lost when people switched to <b> and <i> instead.

Good comments were made on a similar list of underused html elements that was submitted some time ago:

http://news.ycombinator.com/item?id=481067

<q> doesn't seem to work in Firefox 3.0

The page just doesn't have the actual styles applied to it. I can verify it works in FF3 when you style it properly; I use it myself all the time.

none of it seems to work very well at all in Chrome, or my Firefox 3.0

Seems to be a very redundant article.

The only tag I thought was actually useful is <optgroup>, when you have Categories (labels) in your drop-down <select> that you don't want to be selectable.