Well, that's an interesting collection of historical tidbits, some of which I didn't know, but I'd hardly call it "hidden messages". Also I find it amusing that they don't know who wrote what. Francis Scott Key wrote a poem, not a song, and he titled it "In Defense of Fort McHenry". The music is English, though.
http://en.wikipedia.org/wiki/The_Star-Spangled_Banner
All that's ever sung is the first verse. The rest of the poem is just as powerful.
http://kids.niehs.nih.gov/games/song.../anthemmid.htm
Still and all, a nice article.
