Yes, the Beatles, without a doubt, had a massive impact on American popular music. What's always struck me as odd however, is why them? When you listen to their earlier albums, like Beatles for Sale, it's plain that they didn't start out as the revolutionaries (pun intended) that we remember them as. Their sound was hardly original at that point either: something like a mix of the Everly Brothers, Buddy Holly, and maybe a bit of Chuck Berry.What I think first set them apart from other popular musicians in the early 60s, mostly composed of clean cut teen idols like Frankie Avalon, Bobby Vee and Fabien (who was almost completely invented by the Brill Building,) was, I think, the hair; "Arthur" as George Harrison quipped when asked what he called the Beatles hairstyle. That, along with the fact that they started experimenting with new musical styles (as well as other things,) something that Rock and Roll hadn't done in years.Then, armed with a different sound, they started to depart even furthur from the established music scene by changing other things, including wearing silly clothes, growing their hair longer, inserting not so subtle political messages in their songs and giving a Rolls a tacky psycadelic paint job. The problem was, every other music group saw all this, and started to imitate them, until so many groups had hopped on the new band wagon that the Beatles decided that they had to become even weirder to differentiate themselves from all the groups that copied them. This pattern was pretty much repeated until 69', when they broke up. But the chain reaction that they had started countinued, helping to breed Disco, punk, and today, Lady Gaga.Most likely, the ideas that they indroduced will reverberate for decades to come, until musicans cease to be seen as human beings.