the xhtml friends network looks like an intriguing complement to foaf:

"XFN outlines the relationships between individuals by defining a small set of values that describe personal relationships. In HTML and XHTML documents, these are given as values for the rel attribute on a hyperlink. XFN allows authors to indicate which of the weblogs they read belong to friends, whom they've physically met, and other personal relationships. Using XFN values, which can be listed in any order, people can humanize their blogrolls and links pages, both of which have become a common feature of weblogs."

interestingly, the authors dream of creating a "friendorati" service :

"XFN provides the basis for a world-wide distributed network of personal connections. Proprietary data-owning services like Friendster could be to be superceded by XFN crawling and searching sites—a sort of "Friendorati," as it were. The advantage of a Friendorati-style network is that it allows every individual to fully express themselves through personal weblogs and web sites, instead of to the limited degree permitted by a proprietary service's user interface."

if xfn were to see any significant adoption, i'm sure that this would be fairly trivial for dave to fold into technorati. i know it's early, but at this point it would seem that xfn is going to suffer due to a lack of tool support [hopefully this will change ], but more importantly, i'm not sure how useful it is to try to force a relationship model on a blogroll. taking my own "outbound" links as an example, i'm struck by the fact that almost none of the links could be usefully categorized using their metadata.

having said that, i think the concept of "blogroll" metadata is an interesting one and that xhtml friends network could be made more useful if it were extended to be a "blogroll metadata network" that included attributes for content categorization and "ratings". for example, there's a load of implicit metadata in my blogroll - meant mostly for my own consumption. the "chunking" of links and their relative order are clues to what i'm thinking. with just a few more types of attributes a foundation could be easily created that allows people to search for links that point to authors who have an interest, say, in jabber, os x and might be friends of kellan.

then again, at that point you're probably just creating an xhtml version of foaf. but i still stand by the assertion that i'm not sure how useful it is to impose a relationship model on a blogroll. so maybe we need a separate "friendroll", which has the sole purpose of being used as a public rolodex and can be used as a the foundation for decentralized "friendorati" service? i suspect i might be overanalyzing this just a bit.