The concept of federation (as it has evolved with regards to the World Wide Web) begins with the notion of identity. Sending and receiving email, logging in to a news portal, checking bank balances, finalizing travel arrangements, bidding on auction items, accessing utility accounts, and shopping are all possible online services for which you might define a identity. Each time you want to access one of these services, you identify yourself by logging in to the service provider. If you use all of the mentioned services, you've configured a multitude of separate accounts to which you must log in and log out. This virtual circumstance offers the opportunity to fashion a system for computer users to correlate (or federate) their disparate service provider identities. This concept of identity federation allows the user to link, connect or bind the local identities that they have created for multiple service providers. The linked local identities, referred to as a federated identity, allow the user to log in to one service provider site and click through to an affiliated service provider without having to re-authenticate or re-establish their identity.