It’s good to see a no-nonsense explanation of what federation is. I constantly get caught with trying to explain it, and this should save some time. It is interesting to see how this relates to the common "trust" model in enterprise Domains, and hopefully how this will translate into applications usage of such technology. I run into so many applications which have no forthought to integrate into an already established identity model, that I am waiting for true standards to emerge.
Ever hear the term "Federation" or "Federated Authentication" and asked yourself "What the heck is that?". Good question, because Federation has been one of the hottest topics around, especially in recent years with competition heating up from various identity providers and their respective network of services.