I sent in my resume and received an email expressing interest about two weeks later. The email included a link to a challenge with six or seven "challenge" questions. Most were pretty run-of-the-mill, but one was about Dropbox's future potential. Do some research, read some interviews, and you should be fine. Received phone interview invitation less than a week later. Interview was an hour and pretty standard. Ditto next call. And the one afterwards.

Interactions with recruiters was very good overall. They were responsive to questions, but clearly extremely busy with hiring and recruiting, so some responses took longer than others. The first round interview was relaxed and very conversational. My interviewer was happy to answer questions and talk about his own experience as much as learning about me. I talked about what I did at school and answered questions about my resume. The interviewer clearly wanted to to take the lead in the conversation. Dropbox places very high value on cultural fit at every step of the process. Anyone they interview will likely be smart, relatively interesting on paper, and have leadership experience, so It'll be important to talk about your hobbies, special interests, quirks, or whatever "x-factor" you think you have to make you stand out. Even if they don't ask a question that's directly related to it, don't leave the interview without that talking point.