<http://schema.org/topics>
"Android,google chrome,Contests,Dev &amp; Design,developers,development,Events,Google,Google I/O,google io 2011,Google TV,San Francisco-San Jose,software,Tech,Web Apps,web development"^^<http://www.w3.org/2001/XMLSchema#string>
<http://mashable.com/2011/05/02/google-io-2011-tickets/>