It's just one of those things that flourished on the Internet, and as far as I can tell, absolutely nowhere else. When the first webcam was invented, some woman with a ukulele decided to stare directly at the camera and record herself playing a random song, and then every woman between the ages of 14 and 23 decided to join her, and that's why, when the sun explodes and we all die and the aliens come to take a look at all of our historical records, they're going to assume that humanity was like 80 percent big-eyed cute chicks who played ukulele versions of pop songs.
From the full article at Cracked.com: http://www.cracked.com/blog/3-kinds-people-internet-accidentally-invented_p2/#ixzz2kdXvg7Il
A cute girl with a ukulele wrote a song called “Cute Girl with a Ukulele,” and here it is:
It includes the word adorkable.
Lest you think it's all mockery, here's actual cute girl (and good singer!) Zooey Deschanel (and her guitar-playing chum) Joseph Gordon-Levitt with a lovely rendition of “What Are You Doing New Year's Eve?”
I suppose when we talk about “girls,” we should really mean little girls, like this one, who's playing Lazy Song by Bruno Mars on ukulele. She's six.