Oh and Richard I forgot to tell you, may be you're interested in checking also the follow up posts:

* {link:Software Developing: More About Domain Driven Design|url=http://www.pabrantes.net/blog/space/start/2007-01-19/1}

* {link:Software Developing: Domain Driven Design, looking at Persistence|url=http://www.pabrantes.net/blog/space/start/2007-02-28/1}

Regards,

Paulo