Over the last 12 months, I have been building https://learnawesome.org
This idea came from Danny Hillis' 2012 talk at OSCON, which itself was inspired from Neal Stepehenson's _The Diamond Age : A Young Lady's Illustrated Primer_
The dream is to build a tool that matches the right learning material to the right student at the right time. Wikipedia is great, but it doesn't do a good job of leveraging the rich variety of learning resources that exist on the Web. Same applies to GoodReads - which is focused only on books, whereas these days we actually learn from videos, articles, MOOCs, tweetstorms, slack/discord groups, podcasts, livestreams, newsletters, online conferences, apps & games, interactive explorables and much more.
For now, I am building it as a social network for lifelong learners. It's open-source, built with Rails + PostgreSQL, and complies with standards like Dublin Core's LRMI extension of schema.org and ActivityPub for integration with Fediverse. A GraphQL API is also available if others want to build alternative clients.
I have made decent progress so far: Imported thousands of courses and book summaries, built a browser extension for quick lookup/addition to the repository, a spaced-repetition based flashcard practice module. Users can even discover learning resources by recommendations ELSEWHERE (for eg: "Show me books on History which are highly recommended by venture capitalists")
I originally started building this as something to help with my daughters' and my own learning. But it made sense to build this as a public good.
It would be great if you can give it a try, and share ideas on what would make it better.