There were sort of two phases to the interview. I was first contacted via e-mail after applying online, which I think I did through Indeed. I had an initial phone interview with someone from "People Ops" (their codeword for HR), and then an in-person interview about a week later.
The phone interview was mostly about ascertaining my reasons for wanting to leave my current job, reasons for wanting to join ZocDoc, and attempts to align my expectations with what the job actually entailed. I appreciated the phone recruiter being completely up-front about what the job paid. While the pay was lower than what I was seeking, I decided to attend the in-person interview anyway, as the recruiter told me that most people are promoted "within their first nine months" and my current position had no opportunity to advance.
I arrived for the in-person interview a little early, as the e-mail including the interview offer made a point of the importance of punctuality. Given that, I was a little miffed that I had to wait quite some time before my interview actually took place. I was offered bottled water by the receptionist while waiting.
When the interview commenced, I was led to a VERY small room (think phone booth size), and a little while later joined by who would be the first of three people to interview me. The first interviewer asked mainly about my technical experience, projects and responsibilities at my previous job. The next mainly focused on my customer service background. The final seemed mostly interested in my hobbies and personal/education background. The tone was mostly casual, and there were no "gotcha" questions or technical tests. Each person took 30 minutes, for a total of 90, and between wait times between them and the initial wait, the entire process took slightly over two hours.
I took me about an hour to get home from the interview, and when I checked my e-mail I found a request for them to contact me by phone to extend an offer. I ended up accepting because, although the compensation is fairly low for the responsibility of the position, and the hours are a little long, the benefits are pretty much unbeatable and there seems to be a lot of mobility, both vertically and horizontally within the company.