And now, reports CBS News correspondent Allen Pizzey, people worldwide are giving a resounding nod of approval to the latest -- started by Paul McCartney -- a distinct and repeated nodding of the head, as if saying, "Yes!"
It's featured in a home video the 65-year-old singer posted on YouTube, making him the newest, and probably most famous, person to put something on the popular Web site.
In the video, McCartney shows himself and a few friends nodding along to "Nod Your Head," a track on McCartney's latest album, "Memory Almost Full."
The song, asserts Pizzey, "sounds like a nonsense ditty." But the YouTube video, and "the nod," have turned into phenomenons.
Not only has the song become a hit, thousands of people have reportedly added their own versions of "nodding along" to the Web site.
The video even features two dogs from Maine, seemingly nodding.
The dogs aren't in tune with the music. Their heads, Pizzey reveals, are following a piece of chicken being waved in front of them! The clip was one of scores submitted by fans hoping to be part of the video.
As a rock 'n' roller, Pizzey observes, McCartney may be an old dog, but he's still learning new tricks.