Every successful person has their private knowledge base where they keep on accumulating knowledge. The better the structure of the knowledge, more optimally it could be retrived and utilised to achieve the desired goals. 

Obsidian allows you to create notes, interlink them, pull all related notes together on a single page, has a feature to show various topics are interlinked which makes it interesting. 

If you are an avid notes taker, do explore obsidian - https://obsidian.md/