As a reader of my blog you're probably familiar with my love of hybrid cloud environments and their associated buzz words. I've been a big proponent of computing environments that span both local and remote cloud resources and that can scale on a global geotargeted basis. I'd like to introduce yet another Buzz word to my collection, "Cloud middleware"
James Urquhart, touched upon this concept of cloud middleware in his recent post (The Significance of the Cloud Proxy), and I do agree alfresco is a potentially great platform to act as a "cloud middleware". In james post, he uses a consumer example built on the Alfresco platform, but the same general ideas could easily be applied to enterprise usages..
The idea of content centric middleware such as Alfresco as a platform for the enablement of geotargeted services that allow distributed processes running on one or more machines bridging multiple cloud providers across the globe would seem ideal. Cloud middleware should provide for interoperability in support of the move to multi-cloud a.k.a geographically distributed architectures, provding the ability to scale anywhere at any time, for any user. We've been using the Alfresco system for several years to accomplish this sort of thing specifically through it's innovative plugable file store and clustering capabilities. Alfresco is certainly worth a closer look.
I should also note that platforms like 10gen which they describe as a "new platform-as-a-service technology designed to help developers quickly and easily build dynamic, scalable, mission critical web sites and applications" could also fit the bill as well as more traditional platforms such as appistry and gigaspaces. I suppose you could also use the Google App Engine SDK, but that another can of worms.