What Defines Cloud Computing?

I’ve read a number of articles lately and spoken with some industry pundits, all of whom have varying definitions of what does or doesn’t qualify as cloud computing.

I often hear cloud computing getting thrown into the same bucket as grid computing, and while many cloud computing environments leverage grids, cloud computing is the next step and looks to incorporate Web 2.0 and reliance on the Internet.

While I don’t believe there is one end-all, be-all definition, I think the definition of cloud computing ultimately lies with the benefits that users should reap from it: obtaining a wide range of functional capabilities in a pay-as-you-go model without the knowledge, expertise, or direct control over the software. Cloud computing is the realization of the earlier ideals of utility computing without the technical complexities or complicated deployment worries. As part of such services, vendors should be providing customers with an environment that is both economical and scalable while being flexible enough to meet the needs of the end-user.