I've recently been reading about Edd Dumbill's Description of a Project (DOAP) project.
Machine readable descriptions of software projects is something I've dabbled in since 1998 when I started XMLSOFTWARE.COM. Around that time I worked a little bit with Lars Marius Garshol's XML Software Autoupdate (XSA). Microsoft had Open Software Description (OSD), although OSD was more designed for describing component dependencies whereas XSA was designed for software directories to be able to poll to get updates from developers (a use-case DOAP would be suited to as well).
Given that a lot of this site is about open source software projects of mine, I'll probably add DOAP support to Leonardo at some stage, probably around the same time I add FOAF support. But I have the same questions about the relationship between DOAP and, say, Freshmeat or Advogato as I do between FOAF and the Orkuts and Linkedins of the world. Namely: how can I use my own website as the authoritative source of my own FOAF and DOAP information while at the same time that information being available in directories for searching, rating, etc.
The RDF-nature of both FOAF and DOAP means that what is really needed is a general mechanism that does this for any RDF, although FOAF and DOAP specific support would make a great start.
I'm thinking for starters of a version of Advogato where you just specific the URI for your FOAF, DOAP and RSS.