The Amazon Simple Queue Service offers a reliable, highly scalable hosted queue for buffering messages between distributed application components. The Amazon Simple Queue Service reduces the costs associated with resolving the producer-consumer problem that arises in distributed application development. Such costs include increased application development time, and potentially significant investment in server and network infrastructure to support distributed application messaging. Amazon has already invested in the large-scale computing infrastructure that runs the Queue Service, and since the Service's interface is exposed via Web services, integration with applications is fast and easy.
I've been a bystander for some serious networked application development; at one point we used IBM's MQueue. This stuff is non-trivial. So now Amazon is providing a network queueing service?
Very strange. Who would ever depend on it? What's to stop it from vanishing? What the heck are they up to? I have to assume it's the first step is something rather larger.