Metadata is often defined as “data about data,” but a more accurate definition due to Cliff Lynch is that metadata is a set of assertions about a resource. The most common assertions made inlcude the title, description, format and subject of a resource. These are important for several reasons:
Metadata Principles and Practicalities. A reference article on metadata from the perspective of the library and learning communities.
The word “web service” can mean a lot of different things today. The basic idea of all web services is that you can access the functionality of a program running on a different computer using the same protocols you would use to retrieve web pages or submit web forms.