As this piece points out, The Everly Brothers Harmony inspired much of the 60's folk rock sound. I guess I didn't realize how young they were when they hit the top; Phil was 18 in 1957 when they had their first hit. I was raised on the classic rock listening habits of my older brother and I know a lot of classic rock fans consider the Everly Brothers "bubble gum" music. But I always tip my hat to the pioneers. Just as Chuck Berry pioneered much of the rock and roll sound, the Everly Brothers pioneered a vocal sound that dominated the 60's.
And it was a great sound in its own right and the music world has lost a giant.