I am successfully using ACS to login to a web application using Windows Live, Facebook and Google.
Google includes the service namespace in the confirmation message, as below:
(myservicenamespace).accesscontrol.windows.net is asking for some information from your Google Account. To see and approve the request, sign in.
This is correct behaviour, I suppose, because as a user you want to know what is asking for the claim. Windows Live doesn't show anything, and Facebook uses the application name that was set up.
Obviously for users it can be confusing seeing the Google rigour. You come from mydomain.com, and are approving myfunnynamespace.accesscontrol.windows.net.
Is there any way to pass information to Google that will make more sense to the user? I get that you can't change the URL, which Google is looking for. But can ACS pass additional info, such as an application name, or can an 'app' be created like with Facebook?