I was referred by a current employee on Twitter's internal job posting platform (Jobvite). I had created a resume specific to this job and company prior to getting submitted. Once submitted, I was pushed through for a phone interview with the hiring manager. Questions ranged from standards like "why Twitter?" and "why this job?", to ranking my strengths/weaknesses, and citing some of my favorite Twitter ad campaigns. I did 1-2 hours of extensive research before this interview, and after hanging up, received an email within the hour pushing me to the next round. The third round consisted of a mock assignment. Details of the assignment are confidential, but basically I was tasked with creating a deck for a mock client to solve a mock marketing need with Twitter tools. I gave myself 3 business days to complete this assignment but learned after that I could have asked for much more time. Oh well! It took about 3 business days to hear back re: the assignment, and I was asked to come onsite for interviews for the 4th round. I had 5 in person interviews on site, each about 30 minutes - 45 minutes. The questions ranged from an impromptu ideation session to pure chemistry and work style. Everyone was AMAZING--very smart, engaging, warm, and people I would love to spend my days with. From there, it was about 5 business days of waiting. I got an email saying they went with another candidate. I asked for feedback from the hiring manager and didn't receive any, but my hunch is that they with a more senior employee's referral.