A user is anyone who holds an IdentityManager system account. or an Identification of any thing, and that is unique number or value.
IdentityManager stores a range of data for each user. Collectively, this information forms a user’s IdentityManager identity.
this identity could be user name or accout ID or any thing which has to be unique valaue and identfy the individual in any system like
Bank Account Number, Employee ID, Windows User ID, or any thingw which represant the uniqueness of the systems.