Cool news from Ian Davis, Eric Vitiello's relationship schema has a new home at http://purl.org/vocab/relationship/
This is great way to expand on foaf:knows and there are examples of this usage shown using FOAF. Something new is that there are also (X)HTML examples showing relationships between authors of pages using rel and rev attributes on links. Much like the infamous XFN system, but using the same vocabulary as in FOAF. Looks like it's time to update my FOAF file...