I was just playing with liferea. It imported the OPML I exported from my 'brief' firefox feed reader. If you click on a folder, you get the entries from all the contained feeds. Thats largely what jaiku/friendfeed do.
I'm going to extend the XFN Friend Lister to spider the XFN links from a given starting page, and generate an OPML file. The folders will represent groups of pages that are 'me' linked to each other. The friend links will provide fresh URLs to try and group together as individuals.
hmm. maybe it'll be more interesting to work on the SVG graph first.