I'm putting together a presentation on music, and over the next few days will be sharing some of the thinking and research.
Long before file swapping and You Tube, there were dance crazes. The minuet took a long time to spread throughout Europe, because it needed to go from court to court and then trickle down to the local gentry. But in the 20th century, as with everything else, technology made the difference.
The Charleston benefited from the then-new medium of radio. The spread of the Twist wouldn't have been possible without network television. (See Chubby Checker below.)
And the Electric Slide and the Macarena wouldn't have been possible without weddings and bar mitzvahs, though their worldwide spread was certainly enabled by MTV and its cable TV ilk.
Still, what they all had in common was (mostly) girls, practicing the steps with each other in their bedrooms and at slumber parties until they got them just right. Now, YouTube means they don't necessarily need each other - and a good thing, since chances are the minivan trip to a friend's house takes longer than ever and the gas costs three times as much.
Fortunately, your average seven-year-old could not only watch Soulja Boy "Crank That" last year, she could watch, most likely on her own computer in her own room, as he broke it down.
She could also learn all the steps for Dance Dance Revolution, first in an arcade, and now at home for the Wii.
This may or not be progress, but it sure is fun.