Twitter really does prioritize employee referrals so on the one hand, you have a much better chance of landing an interview. On the other hand, in truth, you may not have been considered at all if you applied without a referral but you'll go through an obligatory process.
I was contacted by one of the head recruiters there. We had a 30 minute initial phone screening. She was so enthusiastic about the perks and benefits and very enthusiastic about my prospects for this job.
One week later, she scheduled a phone interview between myself and the hiring manager. That phone interview also took 30 minutes, no curveball questions. He asked thoughtful questions to suss my ability to do well in this role and I thought he was easy to talk to. He said he would send feedback to the recruiter and that I will hear from her.
All of this sounded great and promising at the time. However, HR really dragged the process out until it became a defeating ordeal. I followed up with the HR contact a total of five times over the course of three months. There was no response whatsoever over the three months. I finally received an automated email from Twitter informing me that they had filled the position. People deserve more respect than that. It's interactions (or I should say lack of communication) like these with HR that makes you look at the company in a much less favorable light. Even if they did not have any updates, a simple 1-2 line email to say "We are still reviewing candidates and we will follow up with once we have some news" would suffice. It's just common curtesy. People deserve some communication, especially if they've already moved through the first couple of steps in the interview process.
In the end, I realized that even with amazing perks and benefits, Twitter is not the end-all, be-all of dream jobs.