> But why should XHTML2 have any sort of abbreviation
> element at all?  It certainly isn't semantic. [...]

It does provide semantics because it marks up a part which is an
abbreviation or acronym, like paragraphs or headlines indicate the corresponding text.
Thus it makes sure that there is a standard element you can use to e.g.
highlight text, which might not be obvious to everyone, and it provides mechanisms
to display its description (for example via the title attribute or the
content property, although it's IMO not desirable to have content in CSS).

Like I suggested several times now, rather extend the current set of <abbr
/> and <acronym /> by <term />, or create a generic solution by e.g.
introducing any <explanation /> element.


> The only use that has been given for abbreviation elements
> is as a presentational aid for aural user agents. [...]

No, since you could also e.g. use the span element to have this effect (any
presentational aid):

Example 1 (Markup):

    <span title="World Wide Web">WWW</span>

Example 2 (Markup and CSS):

    <span title="WWW">WWW</span>

    span[title='WWW']:after {
    content: ' (World Wide Web)';
    }


> Actually,  the suggestion to use ruby markup instead
> for abbreviations appears to be the most appropriate
> way to handle them. [...]

No, since Ruby ain't designed for this purpose [1]: 'Ruby text is used to
provide a short annotation of the associated base text [...]. Ruby annotations
are used frequently in Japan [...] also used in China [...]'. Although the
usage of Ruby for subtitles [2] or abbreviations seems to become more popular,
I'm absolutely against it since it's an abuse of Ruby and thus more than
amateurish.


 Jens.


[1] http://www.w3.org/TR/ruby/ 
[2] http://webdesign.crissov.de/ruby-hackx.html  (German)


-- 
Jens Meiert
Interface Architect

http://meiert.com/