My best guess is that it's an elaborate internet scam to get hold of my personal details and use them to, er, send merchandise to my home.
I was recently offered three issues of Mac User and a free gift for £1 (right after my three issues of RiDE for a pound ran out), so it's also possible that this is my freebie, replacing the advertised in-car iPod kit.
The third possibility is that it was a dastardly plot to get the 'Montage' song from Team America stuck in my head. An expensive way to do it - but it worked, damn you.