Wow, very interesting. I too thought it was a 1 man website, largely based on the aesthetics - is that accidental or deliberate? I think the 1 man show might be a better image.
There's a whole slew of designers and UX people, so whatever you see is definitely deliberate. They do a lot of usability testing, not just for the website, but the app, mobile site, etc. You would not believe how many iterations of something tiny like a slight change in the thumbs up button goes through. Everything is related to clicks and revenue, so there's a lot at stake for even small changes.
