I was referred by a friend that works for Facebook, who submitted my resume. Two days later, I was contacted by a recruiter to set up time for a phone interview. During the 30 minute call, we went over my background and sales experience. The second round interview was a phone interview with the hiring manager, which took about the same time. The interview was similar to the first one and consisted of general background questions. The final round of interviews took place at HQ, which was three 1:1 interviews, and one 1:2 mock sales pitch. Less than a week later, I was told I got the offer, which I was very excited to accept.
The whole process (from resume submission to offer) took about 3 weeks. I was recruiting at the top tech firms during this time and my experience at Facebook was by far the smoothest, fastest, and most professionally conducted (a pleasant surprise). It was because of this (along with the very attractive comp package) that I decided to accept the Facebook offer and I could not be happier!