<http://schema.org/image>
<http://rack.2.mshcdn.com/media/ZgkyMDEyLzEyLzA0L2I0L3N0ZWFsdGhzdGFyLmZ6ay5naWYKcAl0aHVtYgkxMjAweDYyNyMKZQlqcGc/cbd90719/d3b/stealth-startup-knocknok-debuts-by-powering-chat-for-the-masters-b998d7626e.jpg>
<http://mashable.com/2008/04/10/knocknok/>