Via Google, I found another question on stackoverflow regarding the differences and similarities between Azure AppFabric and Windows Server AppFabric. It was mentioned that both versions of AppFabric come closer together or even melt together. This post is almost 2 years old and today in 2012, I still struggle with trying to unterstand the plan behind both AppFabric versions.
From my point of view, I worked with the Azure AppFabric (Caching, Service Bus, ACS) and I am familiar with it. But when look at the product website of Server AppFabric, I'm confused. Am I wrong or is the Caching Service the only thing both technologies have together?
Thank you
edit: (At least, caching related classes and interfaces seem to be indentical, is this correct?)
Windows Azure AppFabric as a brand name doesn't exist anymore; the technologies it used to contain (Service Bus, Access Control Service, and Caching) are now part of the Windows Azure "Client Libraries for .NET". You are correct in that the two AppFabrics had Caching in common, but at this point it's best not to be confused by the AppFabric branding. Think of the technologies involved: Windows Server AppFabric, and Service Bus, Access Control Service, and Caching (within this set of articles: http://msdn.microsoft.com/en-us/library/dd163896.aspx).
Finally, although this article is a little outdated, it will give you some of the historical context: http://social.technet.microsoft.com/wiki/contents/articles/1445.aspx.