I've added a new feature to the Gedcom app. Each user's data can be exported as a FOAF (RDF/XML) file.
There isn't much in the way of user data exported (yet), but the neat part is the relationship vocab used. Eric has put together a small, but useful set of terms detailing relationships. This allows me to enhance foaf:Knows to show that person X is the parent of person Y, etc.
My hope is to use the foafnaut source to create neat interactive family-tree diagrams.