== The problem with blog footnotes

Here is something that has just occurred to me (courtesy of seeing an
example of it): footnotes are hard to do well in blogs, and may need
actual software support if you want them to be completely correct.

The conventional way of doing footnotes in HTML is to use fragment URLs
and anchors, with the footnote text at the bottom of the entry and
your choice of footnote markers in the main text. But, like anything
involving anchors, this means that you need to come up with unique
anchor names.

On one level this is no problem; you can just use 'fn:1', 'fn:2', and
so on. But on another level this is a problem for blogs, because blog
entries are repeatedly aggregated together with each other on web pages.
When you put multiple footnote-using entries on the same HTML page, you
need all of their anchors to be unique; you are not likely to get this
if you use 'fn:1' style anchors. (This is especially pernicious once you
start considering syndication feeds and 'planets', that put content from
multiple blogs on the same HTML page.)

You can just punt on the issue and say 'well, it's up to the author to
come up with unique anchor text (ideally globally unique text)', but in
practice people won't always do this and this is equivalent to having
non-functional footnote links under some circumstances.

Admittedly, I suspect that most people won't really care about all of
this, and will be perfectly happy using 'fn:1' style links and having
them not work. Regardless of whether the actual links work, your intent
is likely to be pretty easy for users to follow.

(And who knows, maybe the proper implementation of footnotes in blog
entries is pop-up alt text, like [[xkcd http://www.xkcd.org/]] famously
does on the comics images. Alternately, footnotes are a printed thing
that are not appropriate in HTML.)