I wonder how all that works out for Netflix. They must get a massive discount but do they buy reserved instances? or are all of their instances reserved instances?
And yes, I'd imagine they heavily use reserved instances as their traffic patterns would be pretty predictable by now.
If they do pay the public prices, they are being totally fleeced to the point where you'd have to ask what in the world they are doing.
RIs make such a big difference on your bill if you utilize them well, and it's a no-brainer for Netflix scale.