You can read the full post on Werner Vogels' (CTO of Amazon) blog, All Things Distributed. The note is short and readable, but here are a few of my own reactions.

The paper begins with a problem that Amazon is facing with its current client-server architecture: applications access the database directly and are tightly coupled with the data model. This makes the application sensitive to changes in the underlying data layer – where and how data is stored.

It proposes two solutions: one, a move towards a service-oriented architecture, and two, to model processes as a workflow.