<http://schema.org/description>
"Twitter just became a ratings chart of its very own. Twitter and Nielsen, the major TV ratings system, have announced a partnership to create the Nielsen Twitter TV Rating, a social ..."^^<http://www.w3.org/2001/XMLSchema#string>
<http://thenextweb.com/twitter/2012/12/17/twitter-becomes-tv-ratings-system-nielsen/?fromcat=all>