Shibboleth Service Provider Configuration for Single app for multiple sub domains with Different IDP's

[Cantor, Scott]

> The counter example is Sales Force which uses a feature they call “My
> Domains”, which is a subdomain per customer, to handle the IdP discovery
> process.

That's the example rather than the counterexample. If people think that scales well, we'll have to agree to disagree. But I would add that there's a particular reason why the model is dangerous: it precludes federation (in the true sense of resources accessed by multiple organizations' users) without very bad UI implications because any given URL presupposes the IdP.

Obviously not every app needs that, but on the other hand, a lot of apps think they don't and end up needing it. Google was one of them actually.
 
-- Scott