CKS requires and stores a default number of metadata associated to each entity. To design a community or to meet the needs of a specific application, it may be necessary to define additional information on the data and on the members, like:
- a document categorization specific to an organization (taxonomy),
- the postal address of a user, or
- keywords on the data.
In CKS, metadata on every entity type can be expanded. Additional metadata takes the form of annotations.
An annotation has a name, a type, and a number of values. Its properties can be mandatory (for example, mandatory characters, or lowest and highest number of values).
CKS makes it possible for the integrator and customer to customize entities and the annotations types and values.