Will someone provide some real use case scenarios of how the archived-at URL gets used by a message receipient. If I have the message locally, do I care where it is archived?

It's handy if you are writing a blog. For example, Linux Weekly News reports on the Linux Kernel mailing list. They quote particular messages, and provide an archival link. This lets readers examine the (possibly active) thread.

http://lwn.net/Articles/286910/ http://lwn.net/Articles/287490/