I applied online and received a phone call a few weeks after I applied. The whole process took probably around 9 months-- many, many interviews, usually around 8PM EST, with various people. In total, I had about 8 interviews, not including the final site visit. Each of the interviews were a little draining, consisting of about half an hour of getting-to-know-you type questions to determine if I was a jerk (their words) and then half an hour of engineering questions. After months of phone interviews, they flew me to Palo Alto, where I had a full day of interviews with a variety of people, to include lunch with potential co-workers. The final two interviews of the day were with the two founders.

Several conversations over the phone, then 3 interviews on site. Very positive experience, kind people. interviews did consists of a few brainteasers, as well as how to apply the platform yourself, so make sure you understand it. Also just your standard motivation questions and affinity with technology.