<http://schema.org/topics>
"brightkite,contributor,data,data visualization,Foursquare,gowalla,infographics,location,location-based,location-based networking,loopt,Mashable,Social Media,social networking,trending"^^<http://www.w3.org/2001/XMLSchema#string>
<http://mashable.com/2010/04/06/location-history-infographic/>