The principles of WOA are:

1. It is a resource-oriented architecture (ROA) - so it is based on URIs and hyper-links

2. It is based on the web protocols for discovery and consumption - e.g. granular stateless services using REST much like with SOA.

3. It encourages linked-data - so different apps and data can reuse APIs and vocabularies to support mashups (WEB3.0).

4. Open yet secured

http://hinchcliffe.org/archive/2009/12/14/18179.aspx