There were a few problems with getting the interview initially set up, but once that was organized and cleared up, the interview process went very smoothly. The technical recruiter that I spoke with was very nice and friendly and sounded very enthusiastic about Yelp, which was encouraging. She asked pretty much all the questions that are listed in the other posts, along with a question about INNER JOINS in SQL and a question about SSL.
I then scheduled my second phone interview with an engineer to be a week later, who mostly asked me some questions about the projects that I had worked on, along with a couple more in-depth technical questions about various things. I was not extended an invitation for an on-site interview.