I have gotten as far as doing the onsite multiple times in the last few years. I won't go into the details of the process, as they've been described by other folks, but there's one element I definitely want to point out, which to me is of the utmost importance. After they let me know I failed the n-th onsite, I asked for feedback, and I didn't receive any specific one. This is not new to me, as this never changed time after time. I'd like to point out I interviewed with other companies of the Bay Area before, and there is indeed such thing as a very detailed feedback, which is very valuable information to a candidate! This is not the end of it though. After some time, I got an email with a link to a thorough feedback questionnaire about the last interview process at Facebook. Since I believe in symmetry, needless to say no contribution whatsoever will be given! This is the reason for my negative assessment.