San Francisco (H1B, INTERN welcome):
Klout is in growth mode for most of 2012 and is currently at 30 engineers.  We are looking for research, backend, frontend, QA and generalist engineers.  Our requirements for various positions: machine learning, java, hadoop / hbase, scala, and node.js. We have a goal of becoming one of the Best Places to Work in 2012.
Jobs here:  <a href="http://klout.com/corp/careers" >http://klout.com/corp/careers</a>