<http://schema.org/description>
"Advertisers and brands that run ad campaigns on Facebook will know that sponsored stories provide an incredible return on investment, as a viral ad platform that drives new fans to ..."^^<http://www.w3.org/2001/XMLSchema#string>
<http://thenextweb.com/facebook/2011/07/20/facebooks-sponsored-stories-will-decrease-your-cpa-in-ads-by-32/>