You would have had to have MobileMe when it was a service. It was prior to iCloud. And before MobileMe, it was .Mac.
So - iTools -> .Mac -> MobileMe -> iCloud
Weird. I just realized I have a me.com alias on iCloud and I don't remember signing up for MobileMe at all ever. I think I set these aliases up a couple years ago when I started using iCloud Mail more and I seem to remember @me.com being an option then. I guess I could be wrong.
edit: I just did some research and I am wrong. I guess I have a "limited edition" email address? If they ever beef up iCloud Mail a bit, I might be tempted to finally switch over from Gmail for my main personal account.
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