"The other day I did a security workshop at a firm here in Sydney and one of the things we did was a proxy a bunch of traffic and inspect what was going on behind the scenes. Among the expected hilarity that always ensues from these sorts of exercises (you can find heaps more of this in my Hack Your API First course), one of the guys at the event found this in the response headers of Airbnb: X-Hi-Human: The Production Infrastructure team added this header. Come work with us! Email [email protected]" - CW