In general, last time I looked at AWS it made sense from 2TB to 30TB a month, and under 400k connections a day. If either range was exceeded, than the service

In general, last time I looked at AWS it made sense from 2TB to 30TB a month, and under 400k connections a day. If either range was exceeded, than the service ceased to be the economical choice when compared with CDN providers, and colo/self-managed unlimited-traffic options. For example, if you primarily serve large media or many tiny files to clients that don't support http Multipart Types, than AWS can cost a lot more than the alternatives. However, AWS is generally an economical cloud provider, and a good option for those who outsourced most of their IT infrastructure. The article would be better if it cited where the variable costs arose.