We make use of the Shadowbox plugin (a great overlay plugin for iframes, etc.), and to use it you have to define a link's relation. So, like:
'.. href="xxx" rel="shadowbox;other stuff and parameters">xxxx</...'
This works great for hard-coded links on a page, but how do I modify rel = whatever via the links database? You can use the "Link Relationship (XFN)" section, but you actually have to hack the file to be able to enter whatever you want in there, then whenever you update WordPress, you have to hack it all over again. There has got to be a better way. Does anyone know of a plugin, or an easy way I just add my own rel=whatever?