Of course the technique I outlined a few days ago isn’t limited to favicons. It can be used with any appropriate image. I realised that I could make links to Live Journals look exactly like they do on LJ itself by including the following in my CSS.
#content a[href^="http://www.livejournal.com/users/"] {
background-image: url('http://stat.livejournal.com/img/userinfo.gif');
padding-left: 20px; background-repeat: no-repeat;
}Still Gecko only obviously, due to the use of the CSS 3 selector.
What I should do is cobble something together in WP that automatically converts <lj user="foo"> into an appropriate HTML link complete with icon. This is the sort of thing that Live Press was supposed to do but (a) I could never get it working and (b) it hasn’t been upgraded to Word Press 1.5. Time to brush up on my PHP and get hacking.