I applied online. The process took 2 months. I interviewed at OpenX in May 2015
Interview
Was a very long process, ended up spanning over a couple of months. I had a difficult time contacting the recruiter and got passed around a few times. To be fair there were multiple roles I was being considered for. Two interviews were about 3 hours each, so I spent a fair amount of time in the building.
Interview questions [1]
Question 1
Asked me how I would prioritize an impression coming into an adserver. How I would evaluate it - just on price, or fill rate or a metric to combine both, ect
I applied online. The process took 2 weeks. I interviewed at OpenX (Pasadena, CA) in Feb 2013
Interview
Straight-forward, thorough and polite. Very welcoming team. Went through the standard phone screening with the HR department, then spoke to a manager for basic review. I was then invited onsite to meet with relevant staff and management. Overall a very good experience.