<http://schema.org/description>
"Twitter has today updated its app with a bunch of improvements including performance and launch time stuff. But the big addition is support for Twitter's new Cards types, including ..."^^<http://www.w3.org/2001/XMLSchema#string>
<http://thenextweb.com/twitter/2013/04/03/twitter-for-ios-updated-with-support-for-its-new-app-install-and-launching-cards/>