StumbleUpon, San Francisco, CA.
I have been working in the Applied Research team here @ StumbleUpon for the past 3 weeks and it has been a fun ride so far. They are hiring folks in three different areas (Search and Recommendation, Analytics and Applied Research). We are looking for folks who have been doing a lot of ML( recommendation systems, statistics), search and have experience scaling up (E.g. Hadoop). Refer : <a href="http://www.stumbleupon.com/jobs" >http://www.stumbleupon.com/jobs</a> for more descriptive details.
Although we have been here for a while, we have been doing significant changes to our system which will be an exciting opportunity for some one to own and work on large scale machine learning projects. The company is profitable, has the usual goodies (nice salary, 401K match, gym, Uber/Commute reimbursement etc). Anyways, if any of this sounds interesting to you, email me @ REDACTED_EMAIL and I will answer any of your questions and help get you in touch with the right recruiters ASAP.
Ask HN: Who Is Hiring? (July 2012)