I read when Craig originally asked for this footnoting plugin, and I don't remember it being that hard. In fact, I wrote a good percentage of the thing, and got distracted before I had a chance to clean it up.
Now Jeremy Curry has already released the excellent Linknotes and it seems like I'm a little late for the game. Well, maybe not...
My linkfootnotes plugin does essentially the same thing as Jeremy's. But instead of using the Textile syntax, I've employed the rel="" parameter of the anchor tag. So instead of having to remember the Textile method of adding links and then the Linknotes extension to that to enable the footnotes, You just add rel="footnote" to any existing anchor tag, and presto! -- It becomes a footnote.
There are a couple of nice things about this. The first thing, dealing with remembering how to do it, I mentioned above. Also, now that I'm thinking about it (since I'm writing this post with it) using rel="" could work in the WordPress 1.6 WYSI editor, whereas I'm not so sure about the Textile markup.
The second thing is if you disable the plugin, your links all still work, they're just not footnotes. I'm going to guess (haven't actually tried it) that if you disable the Linknotes plugin, then strange things happen to your links. I could be totally wrong, but that's my guess based on the syntax.
So how do you specify the text to use for the footnote? You use the title attribute. If you don't specify a title attribute, then the text that is in the anchor tag (between the matched opening and closing tag) is used. If you link two things to the same place, only the last title tag in the post is used to form the footnote.
Anyhow, I don't know if anyone will really use it, but you can see its output on this post. If you do want to download it, you can find it over at RedAlt.
