From W3C Wiki
-  Nepomuk Message Ontology - its used in aperture.sf.net, its used in nepomuk.kde.org, and tracker is working to support it someday. It may soon be on your cellphone when you use a new Nokia Maemo and its tracker backend. Its actively developed on oscaf.
- swap/pim/email vocab, supported by aboutMsg.py (@@and mid_proxy.py?)
- A Knowledge Base about Internet Mail, in progress Feb 2002 by DanC. extracted 18MB of RDF/xml about 16000 messages. mid_proxy.py proxies IMAP queries over HTTP, with results in RDF (or HTML). also: extracting RDF from RFC822 formatted email July 2000 to rdf-interest
- see also:XMTP A mapping from RFC822/MIME to RDF/XML by JonathanBorden
Internet mail message header format by D. J. Bernstein
discussion Sep 2001 about modelling header fields such as To: