Claims
Claims are simply key/value pairs that represent the identity data associated with the user. Claims allow for any key/value pair and any number of claims are allowed. This allows the manipulation of arbitrary data on the user and this data can then be used by an application, assuming the correct claim types and values are used. From the user interface and RESTful API, claims can be added or removed.
In an IIdentityManagerService implementation, the IdentityManager claims are typically mapped to the traditional Claim concept and class in .NET. This means that they are typically stored as key/value pairs in the underlying database, but could technically be stored in any way desired.
When reading the user's details, the claims are modeled via ClaimValue on the UserDetail class.