From the discussion in our last class, I thought it would be interesting to point out what elasticity means in regard to Amazon AWS.
"Elastic – Amazon EC2 enables you to increase or decrease capacity within minutes, not hours or days. You can commission one, hundreds or even thousands of server instances simultaneously. Of course, because this is all controlled with web service APIs, your application can automatically scale itself up and down depending on its needs."
This clearly means that AWS as a service provides well defined API for the applications to scale up and down, but does not do this itself.
FYI: Nevertheless, there is an AutoScaleUp functionality provided by AWS for Web Applications hosted on EC2 which increase the number of resources deployed when there is increase in web traffic. But I doubt if this is possible for other applications too.