Explaining REST to Damien Katz
This is an excellent summary of REST, why SOAP services should be considered broken and why your services should be RESTful. One overlooked benefit of REST: interacting with the HTTP ecosystem correctly. You might not be using a caching proxy on the server-side but if your clients want to use a caching proxy, making your service RESTful means it will behave correctly in unexpected, but legitimate, network architectures.
One fact I did not know: PUT is idempotent, POST is not.