On January 15th 2001, Wikipedia launched.
It has its faults, it has its detractors and abuse. But it's also one of (if not the) most popular websites on the Interwebs.
It made official the decentralization of knowledge for the masses: you're a random expert on a bacteria in a specific kind of cheese? Chime in. No need for someone to write a book on the topic, publish it, and spread it around university libraries anymore!
Of course, it also re centralized knowledge in a way. It is the default encyclopedia, after all.
But I love seeing students going down the rabbit hole of tech I pointed to and learning things.
Even if the articles aren't the best about a topic, they contain enough to fan the flames of curiosity, and to me that's a win.