These guys figured out that if you're going to have a hit song, you need to use these same 4 chords in your songs. They actually go through the all the hits that have the chords too and it's actually pretty surprising the songs that they found to have the same chords. There's "Whatever it Takes" by Lifehouse, "Poker Face" by Lady Gaga and even "Can you feel the love tonight" by Elton John from THE LION KING!! And, that's only 3...there's still 37 others!