<http://schema.org/topics>
"contributor,Facebook,features,Foursquare,geolocation,geotagging,gowalla,location,location-based,location lists,location networking,loopt,mainstream,Mashable,Social Media,Twitter,yelp"^^<http://www.w3.org/2001/XMLSchema#string>
<http://mashable.com/2010/05/13/location-mainstream/>