I have seen some folks selling their PKM databases on gumroad. Usually using Roam Research.
I think its a wonderful way to learn about some topic or discover new subjects.
Think of it as an ever growing online encyclopedia. Imagine crowd sourced databases about biotech, defi & other topics. Are there any existing solutions?
I have slowly planned out a project similar to this. I'm interested in having a tool which allows for shared collaboration on various lengths of content (e.g. lists, guides, etc.). While I don't think it will lead anywhere (there are plenty of great note-taking platforms already) it will be a fun exercise.
I cannot recall how many hours I've spent there going deep into some rabbit hole, browsing pictures of old Sony devices from the 90's.
The only reason I stopped using was because, like many modern apps, I couldn't get over how slow it got over time. I wish someone built a mix of Pinboard and Are.na, where you could save your things - including media - privately and explore what other people have been creating, while still being fast.
I'd love to join a network/platform that allows for plugging in private backends for hosting media content while simultaneously allowing sharing lists and other boards
Besides Wikipedia, check out Arena[0].
[0]: https://www.are.na/