I'm supposed to come up with cost estimates ... at 100k users ... at 1 million users. I've estimated the hardware ... also the Amazon EC2 instances if we go that route.
But how do I estimate the bandwidth? I've tried measuring bandwidth I use in a given time using a "comparable" website (using Chrome's developer tools). My extrapolations have an "average" user using 480 MB/month from the regular server and 1.4 GB/month from the CDN. Cost calculations at that level are crazy high.
What is a good estimation method? Or do some of the big players publish their bandwidth usage?