How we manage development and operations at Etsy

I just found a new reason to love Quora: questions people ask can spur you to write about topics you’ve had kicking around in your head for some time. Such was the case with this one:

How does Etsy manage development and operations?
Etsy seems to have scaled far and fast, whilst continuing to add new features; how is all this managed – is there a strictly-defined process within which engineers operate, or is it a case of hiring clever people and letting them get on with it (Facebook-style)?

I posted my answer, and cross-posted it to the Etsy engineering blog, too.