On the link, I was hoping for your take on it rather than a site that explains what I just did. Especially since you said it after F, G, and I 6th chords. I believe the Neapolitan concept is an Italian concept, but I don't see the similarities. Schuman wrote something on it that was very interesting, although I can't recall what exactly it was called.
"My whole life is a dark room...ONE BIG DARK ROOM" - a.f.i.