Pros
Many promotion and raise opportunities if you do great work. Many smart people to learn from. Product is getting better and better. Business is doing very well. You will learn many interesting things about running a large website. Company favors incremental changes with metrics and emphasizes speed to market.
Cons
Nearly impossible to do an overhaul of a major page or a component, because it's so metrics driven. But it does happen sometimes, if the person pitching the idea is persuasive enough. Related to the previous point, it's hard for designers and engineers to innovate and get company to invest on various ideas so they keep those to themselves. This is reflected by low hackweek participation rate and low activities in open source community and local tech events.
