Retrieving a List of Categories
Before a client can retrieve a list of categories associated with a weblog or collection (such as a photo album), the client must first retrieve the URL associated with the service.categories link relation found in the Atom Introspection document (see Retrieving a List of Weblog) corresponding with that weblog.
Here is an excerpt from an Atom introspection document. The service.categories link relation contains a reference to the URL from which a list of categories can be retrieved.
Once you have retrieved the service.categories URL, an Atom client can perform an authenticated HTTP GET against it. The document returned will contain a list of categories associated with the correspondi
