Applied online. Got an email back from a recruiter over a month later. Apparently they recruit as a team, because during the process I received correspondence from three different recruiters. Phone interview with the hiring manager went well enough for an in-person visit. The office in downtown San Francisco is nice, with everything you'd expect from a dot.com 2.0 company: renovated oldish brick building, everyone dressed in Yelp red, open seating, and conference rooms with crazy names.
The first interviewer was a team member in the Phoenix office, and there were three subsequent interviews with local team members. Yelp is a pretty much Mac only, so questions revolved around Mac troubleshooting, network configuration, and the like. More questions seemed like they were trying to fish out how I would integrate into the team. I think fit is a big concern. They also offer only contract-to-hire positions. The whole process took about two hours.
Got a form email back from the recruiter about a week later that they had passed on me. All the while I never knew what the salary range was, and it was strange that it wasn't until the interview that I found out that it was a contract position.