Unusual guitar tunings can inspire some great songs. It was certainly the case with The English Beat's "Save it for Later" (http://www.youtube.com/watch?v=0bM0wVjU2-k) which was written as a result of the singer Dave Wakeling's experiments with the concept. Open tuning is a better name for it, actually, and it's been integral to the sound of artists as various as the Rolling Stones, Nick Drake and the Velvet Underground. One reason for it leading to creativity is that it can turn the guitar into a stranger, technically speaking, because the notes on some of the strings have changed places. Therefore the guitarist has almost no choice but to be creative, because all of his or her stock phrases, voicings, licks, and so forth are no longer accessible. (I remember hearing one guitarist say that a big danger for those who play the instrument is that by constantly going back to familiar places, "the guitar can end up playing you".) Another related idea is the fact that some writers compose using an instrument with which they're relatively unfamiliar to avoid the cliches that are the inevitable result of learning music. Perhaps cliches is too strong a term, maybe vocabulary is better, because I don't want to sound like I'm denigrating memorized patterns - serious playing is impossible without them, but for the purpose of writing, they can be, and usually are, counter-productive.

Back to the tune in question. I think it's safe to say that you'd know you'd written a good song when Pete Townshend wants to cover it, which was the case here, but apparently he had to phone Dave Wakeling to get help with the tuning first. (It's D-A-D-A-A-D, by the way.)