I heard some discussion over exactly what Cloud Computing is, comparing and contrasting with SaaS, Utility computing, Grid computing, and Autonomic computing. I believe most agree that Cloud Computing has aspects of all these plus the characteristic of server transparency to the application and user.
The Hadoop session had some users who were experimenting with the technology. For example, one individual from DOD had taken 23 Playstation3 and was running map/reduce between the systems and also on each of the cell co-processors.
During the Cloud applications session there was a lot of discussion about how to improve applications. One speaker thought having stateless applications improved portability wihile another thought that middleware could manage state transparently to the application.
My general observation is that Cloud Computing is still embryonic with a need for standards developed to allow application transparency accross Clouds provisioned by different vendors.