<http://schema.org/headline>
"Duolingo introduces gamified virtual store to its iOS app to keep language learners engaged"^^<http://www.w3.org/2001/XMLSchema#string>
<http://thenextweb.com/apps/2013/12/12/duolingo-introduces-gamified-virtual-store-to-its-ios-app-to-keep-language-learners-engaged/>