<http://schema.org/description>
"Facebook recently introduced the world to its Open Graph vision and with it came the Facebook 'Like' button.\r\n\r\nPrior to the Like button, Facebook had its own retweet, like Share button ..."^^<http://www.w3.org/2001/XMLSchema#string>
<http://thenextweb.com/socialmedia/2010/05/23/has-facebook-just-merged-its-like-and-share-buttons-apparently-so/>