Three interviews. Each was a 1:1 with a Senior Executive. The firs two were in a location near my college, then the third and final was at the main SF office. Each interview had two interviewers, each 1:1 though. So I guess you could say there were 6 interviews total.
Each interview consisted of the same type of questions: tell me about yourself, what was your biggest challenge and how did you overcome it, blah, blah, blah. No case tests/studies though the entire time.
After my first interview I called the HR rep who was coordinating with me after 2 week of hearing nothing. At that point I was told I made it to the second round. After the second round, I heard back from the HR person within the 2 weeks, and after the third round of interviews I received a phone call with the offer.