Incredibly beautiful, possibly because it maps so well to the mental model we typically use to organize knowledge in our heads. I don't know how we lost the folder/container vs. document/content iconography, and other things (like layout of items, sorting) during the shift to web applications.
It is nice. I randomly click on something interest just appear in my mind and lead to this: life -> death -> last_words -> More milk. But I can't find it on Wiki. I search More milk. and the first result is this page: https://en.wikipedia.org/wiki/Death_of_Michael_Jackson. Hmm, why is the name different?
> After several hours and several drug injections, Jackson was still unable to fall asleep, and, according to Murray, was repeatedly asking him for "milk", a nickname for the powerful surgical general anesthetic propofol, which Jackson had used in the past as a sleep aid. At 10:40 a.m., with Jackson still not asleep, Murray relented to his requests and injected him with 25 milligrams of propofol diluted with lidocaine. With Jackson finally asleep, Murray testified that he left his bedside to go to the bathroom, and after returning two minutes later, discovered that Jackson was not breathing and had a weak pulse.
This is genuinely a really fun way to browse Wikipedia. Only drawback is that folder names that contain ellipsis don't show the full name when clicked.