<http://schema.org/topics>
"blogging,BLOGS,Business,contributor,event planning,Events,Facebook,features,flickr,justin.tv,Lists,live blogging,livestream,livestreaming,Marketing,Small Business,Social Media,social networking,social networks,Twitter,ustream,web"^^<http://www.w3.org/2001/XMLSchema#string>
<http://mashable.com/2010/02/09/promote-offline-event/>