<http://schema.org/description>
"Google has updated PageRank, the link analysis system Google uses to rank individual pages on the net. Whilst some sites have seen increases, virtually everyones Twitter profile page ..."^^<http://www.w3.org/2001/XMLSchema#string>
<http://thenextweb.com/2009/05/28/google-updates-page-rank-twitter-profile-page-ranks-beating/>