From the end of the '50s to the start of the '60s, the kids kicked off their shoes and started shaking all over the place. These were the sounds they moved to, back in the days when doo wop and R&B were just another way of saying "rock & roll."
Not quite country, not exactly folk, not really rock, and not strictly blues, Americana is the sound of American roots coming together in a melting pot of sound.
Some songs just have a certain je ne sais quoi; when you hear them you start skipping down a crowded public street. Embarrassing? Absolutely. Will you care? Not likely.