Seeing this resolution to the mystery made my day. It's refreshing to see that all this buzz was the result of a glorious postal mishap, not a concerted effort to hijack our attention with a viral marketing stunt.
I was hoping for a new Alternate Reality Game, along the lines of I Love Bees [1] or The Beast [2]. Advertising or not, some of this "viral marketing" can produce large, immersive narratives.
[1] http://en.wikipedia.org/wiki/I_Love_Bees
[2] http://en.wikipedia.org/wiki/The_Beast_(game)