Pros
I worked at Yelp for several years, and will always miss the people. Yelp felt very family-like: friendly and open-minded folks, good communication throughout. These are folks you would want to hang out with on the weekends like BFFs. In fact, I might be spoiled by them; I now expect the same kind of warmth and friendliness from future employers and colleagues. Good supply of snacks and drinks. The current office (140 New Montgomery) is beautifully done, though might be a little too spread-out for some areas. Average compensation, though the benefits (401k, health insurance) are pretty average. From the engineering side, the codebase is so old and badly written in many places, that, depending on what team you're on and the kind of challenges you fancy, this can be a godsend (you love fixing things), or a curse (you love new stuff). I might have a long list of cons below, but I still would recommend Yelp.
Cons
I feel like Yelp may be over-reaching on their core values. They have a vision, for sure, but it's a very broad vision, and not very focused. The higher-ups tend to wear rose-colored glasses when discussing company statistics. I wish they were a little more humble and frank. Also, at times the company seems risk-averse. Expanding to other countries: no problem. Delivering a better user experience: jump through bureaucratic hurdles. Certain projects can takes years of planning and back-and-forth because they really don't want to lose users or revenue, however small that may be, and/or managers keep leaving. Innovation takes a back-seat. Previously, I mentioned the codebase. It's... so ugly that implementing innovative features is an absolute chore. Deploying code is done serially through a person rather than an automated parallel system, which became a HUGE bottleneck when the engineering department grew astronomically in the past couple of years. Lastly, growth. The company is growing fast, and not really in a good way. I can only speak for the engineering department, and it grew a LOT during my time there. Unfortunately, the industry-experts:new-grads ratio is very low. As a result, you'll get one-year Yelp employees mentoring new hires, and sometimes, a one-year employee ends up as manager. Not that that employee doesn't deserve it, but there are still two- and three-year folks around, and they get passed over.