The IT world has a rich vocabulary, and some of it is fuzzily defined or widely misunderstood. A case in point is the discussion around cloud computing, software as a service (SaaS), and hosted services. These terms are sometimes used interchangeably, but each has its own meaning. If your company is debating the merits of cloud computing, SaaS, and hosted services, knowing what each term means will help make your choice more clear.
Definitions for each term vary depending on the source (that's the fuzzy part I mentioned above), but I recently came across a paper that puts it into perspective. Cloud Computing: A Collection of Working Papers was written by Thomas Winans, principal consultant at Concentrum, and John Seely Brown, co-chairman of the Deloitte Center for the Edge.
The report is well written and accessible. I recommend it to anyone caught up in the confusion around these terms.