<http://schema.org/topics>
"aggregation,alltop,blog discovery,Blogger Lists,Blogging Lists,BLOGS,content curation,Content Exploration Series,features,Flipboard,Lists,Mashable,myalltop,paperli,postpost,Social Media,technorati,utopic,yourversion"^^<http://www.w3.org/2001/XMLSchema#string>
<http://mashable.com/2011/04/11/blog-discovery/>