<http://schema.org/topics>
"Business,Business Lists,contributor,Facebook,features,Foursquare,Harvard,Lists,livestrong,Nike,Small Business,Social Media,social media marketing,starbucks,Twitter"^^<http://www.w3.org/2001/XMLSchema#string>
<http://mashable.com/2010/04/08/social-media-real-world-action/>