With the FOAF version we have tho option to collect any data about a person in one file. To be precise, this is not exactly about FOAF, but indeed about RDF. This is a common metadata format. It is possible to include these data directly into xhtml using namespaces. For html this is not possible. But at least you can include a link to that file in the hml head:
link rel="meta" type="application/rdf+xml"
This link serves for autodiscovery.
FOAF is about persons. A FOAF file can contain more than one record about more than one person. A simplified record might look like this:
foaf:homepage rdf:resource="http://www.rorkvell.de/" /
foaf:img rdf:resource="http://www.rorkvell.de/sigi04.jpg" /
To keep track of whoes personal profile this is there is another record: PersonalProfileDocument.
FOAF offers a bundle of data items regarding persons, but f.ex. it does not offer address markup. So for including these and other data types into an RDF (FOAF) file just use an appropriate namespace: