Cloud Computing

Cloud computing, it quite new to me,it seems like grid computing, utility computing or even like a software service.

According to wiki, it is Internet ("cloud") based development and use of computer technology ("computing"), whereby dynamically scalable virtualise resources are provided “as a service” over the Internet. Users need not have knowledge of, expertise in, or control over the technology infrastructure ("in the cloud") that supports them.


But for me, i still confusing about definition for the Cloud Computing, is it must be pay per used basis? or software service plus the scalable resource ? I still need some time to figure it out.

Anyway, I knew that Amazon, amazing "book seller" is one of the success company in the cloud industry with the storage service, computing service etc. Seems like cloud will be one of the top technologies in this year.