Cloud computing vs Utility Computing... Different?

I have been reading recently alot about cloud computing…web articles, books, papers and though I had a good grasp of it. Then I read utility computing defined as a distinct topic. From the definitions of utility computing I have read I’m not sure I would seperate the two concepts. Utility computing seems to me a part of cloud computing.

What are peoples views on this? I realise there is no standard definition of either as far as I can tell…but just would appreciate other people’s views on the matter.

Thanks in advance.