I've noticed girls wearing these out and about. They usually seem to be paired with a tank top, a wide belt, and flats. Cute, but I always wish their skirts were about 4 inches longer. Not just for modesty's sake. (Though can you imagine trying to pick something up off the floor in one of these?) My real complaint is one of proportions. I think a knee-length gathered skirt is flattering because the poufiness of the waistline is tempered by the weight of a longer hem.
I usually make my skirts 24 inches long, which hits right below my kneecap. The longest gathered skirt I could find at Anthro was only 20.5 inches long.
The irony, though, is that I'm always complaining about the long length of vintage dirndl patterns. For my full gathered skirt from VoNBBS, I had to take a good four inches off of the pattern. Of course, hemlines are one of the most quickly shifting and provocative elements of fashion history. There are even economic theories surrounding hemlines, as well as a handy "abstract conceptual hemline overview chart", if you're really interested.
What do you think of these lengths? Do I sound like a cranky old fuddy duddy?