Traditionally, identity management has been a core component of security infrastructures, where it is used to maintain account information that allows users to log in to a system or a limited set of applications. An administrator issues accounts so that resource access can be restricted and monitored. Control has been the primary focus for identity management. More recently, however, identity management has exploded out of the sole purview of information security professionals and has become a key enabler for electronic business through a technological innovation called federation. This innovation was not a revolution, but an evolution, came about as a result of the increasing number and complexity of online distributed systems that both house and manage some portion of our identity.
Federation is the combination of business and technology practices to enable identities to span systems, networks and domains in a secure and trustworthy fashion. This is analogous to how passports are used to assert our identity as we travel between countries.