1. Provide username/password to those parties and then they can use services through web (site).
2. Publish services as web services and give WSDL to those parties so they can consume.
I am not sure if both options are even comparable or not?
Originally posted by Ulf Dittmer:
A web site is for human (i.e., manual) consumption, while web services are generally used for machine (i.e., programmatic) consumption. So the question is actually one for you to answer: what makes sense for your users?
They are human and consume services manually as they have to do further processing that requires human knowledge.