The Web Services Management (WSM) label is used to describe all of the middleware that enables program-to-program communication between "consumer" software and the Web service "provider" software.
This middleware is implemented as a gateway or proxy that can process the XML messages as they travel to and from the Web service.
WSM functionality falls into four major categories: Security, System Management, Standards Interoperability, and Service Virtualization.
The best solutions in this space don't require any changes to the Web service or the consumer software, they allow all the needed configuration to be done declaratively through interface and rule definitions without any programming or complex XSLT scripting; they integrate with existing building blocks such as identity management systems and system management dashboards; and they allow you to address all four functionality areas in a single installation so you don't have to have all your XML traffic going through multiple gateways from multiple vendors.
A fundamental goal of Web services is to achieve loosely-coupled application communication. By loosely-coupled we mean that the Web service interface can be defined without knowing in advance who all the consumers will be, and new consumers can be added without having to modify the Web service. We have achieved this kind of loose-coupling with other networks. We use SMTP e-mail for person-to-person communication, we use HTML for person-to-program communication. We don't have to have to execute an IT project every time a new participant joins those networks. With XML and Web services we are trying to achieve the same loose-coupling for program-to-program communication.
WSM infrastructure allows you to achieve this loose-coupling while effectively dealing with the realities of our IT environments. Such as the fact that we must secure these XML interfaces into our fundamental business systems, we must monitor these lines of communications, and we must deal with inconsistent or incomplete standards implementations. If we attempt to directly connect Web service consumers and producers then these realities produce a tight-coupling. In the real world consumers and producers consistently have different security mechanisms, different monitoring assumptions and different standards implementations. Creating direct connections between them will create the need to coordinate on those issues. Connecting via WSM infrastructure lets you resolve those inconsistencies within the WSM infrastructure itself.