<http://schema.org/description>
"Location-based services like Foursquare may have popularised the idea of 'checking in' using an app, but the concept has since been expanded into a number of different directions by ..."^^<http://www.w3.org/2001/XMLSchema#string>
<http://thenextweb.com/apps/2011/08/04/beyond-location-7-more-things-you-can-check-in-to/>