Notion is a good knowledge management tool for small teams collaborating. Their pricing model is per-seat.
Wikipedia and GitHub can allow millions of people to collaborate on a single page / repo, which would be unaffordable with Notion's pricing model.
WeWrite intends to be as beautiful and easy as Notion, but able to scale to millions like Wikipedia and GitHub.
Replacing Wikipedia with thousands of personal competing / disagreeing wikipedias - Warring communities
Replacing GitHub (for code) with GitHub for Thought