I came across a blog where Peter Laird is doing some nice acronyms on “aaS”.

“Ever wonder what all the “aaS” acronyms mean? Do you want to understand how they relate to each other? This blog entry will help. I have created a map of many of the “as a Service” terms you will see in IT and have grouped them according to category. I have also provided an explanation and links for further reading for each so you can quickly come up to speed on all” 

Full story here: http://peterlaird.blogspot.com/2008/05/saas-soup-navigating-a-service-acronyms.html