rel-me
rel="me"
XFN 1.1 introduced the "me" rel value which is used to indicate profile equivalence and for identity-consolidation.
rel="me" is used on hyperlinks from one page about a person to other pages about that same person.
For example, Tantek's Pownce profile has:
<a href="http://twitter.com/t" rel="me">Twitter Profile</a>
Publishers can use the XFN creator form to create rel-me hyperlinks.
screencast
Watch David Recordon's excellent *30 second* explanation of XFN rel="me".