The interview process can seem disorganized - probably because they interview so many people it's hard to keep track of the schedule. I had 2 phone interviews, both with Product Marketing Managers. They asked questions you would expect: Why do you want to work at FB? What do you want to work on at FB? What's your favorite FB app and why? How would you improve your favorite application? After passing the phone interviews, they brought me out for an on-site interview. I met with 3 PMMs - one interviewer was late and there was general confusion about the interview schedule. But in general, every one was very nice. The work environment is open, casual, and dynamic. Every one seems genuinely happy to be there. One word of advice: there aren't any tough interview questions to help separate you from the pack, so I think you need to be prepared to step it up during the interview and impress them on your own. Clearly, I didn't receive an offer so this is just my guess.