<http://schema.org/topics>
"brightkite,friendfeed,images,Lists,mobypicture,Photo Lists,photo sharing,Photography,picktor,pikchur,posterous,skitch,Social Media,twitgoo,twitpic,Twitter,Twitter Lists,twitxr,yfrog"^^<http://www.w3.org/2001/XMLSchema#string>
<http://mashable.com/2009/05/19/twitter-share-images/>