The argument is that most of your day-to-day social interactions are already on your computer - in the shape of address books, in your email and in the documents you create - even in your blogrolls. Why create an expressive XML language like FOAF, when all you need to do is use ambient metadata? Especially when it's already expressed in a semi-structured form.
Hence SNARF, or the Social Network and Relationship Finder, a tool to help triage your mail.
The SNARF UI is designed to provide a quick overview of unread mail, organized by its importance. The UI shows a series of different panes with unread mail in them; each pane shows a list of authors of messages. Clicking on a name shows all messages involving that person.Worth looking at - and reading the papers.
SNARF gives the user the freedom to build their own ordering. Each person in their inbox is assigned a set of meta-information: "number of emails sent in the last month," for example. These metrics can, in turn, be combined to create an ordering across all contacts.
I wonder how it will cope with my several tens of thousands of email messages.