I interviewed at flickr around 2006 when they were doing a big batch of recruiting post yahoo buyout. Everyone was super nice (I was pretty nervous), but I walked away most impressed by John Allspaw. He was smart, patient and funny during the 30 minutes or so that I spent with him. Since then I've read his blog and come to realize just how valuable to flickr he probably was. Everyone knows who Caterina and Stewart and Cal are, but I imagine Allspaw was every bit as important to their success.
Nice pickup for Etsy.