I was contacted by a recruiter, followed by an interview and a writing test. The test was mainly about your language skills (for specific position) and problem solving for a specific case. About a week later, I was arranged an face-to-face interview with Facebook representative at their office. The questions are about your profile, your understanding of the job and your interest.

covering most of the behavior questions, it's not very hard if you have thought through. also including the analytical think part. i think the most important thing that this company looking for is thinking capability. learning capability is a must, otherwise you will be very painful.