A knowledge base is a connected body of reference material: structure, names, links, and enough context that a reader understands why a file matters. A shared drive is just storage, and storage tends to become a storage closet. A knowledge base stays navigable because the pieces point to each other.
Wikipedia is the familiar example. You read one page, it links to another, and that page links to a related concept. You move through connected knowledge instead of isolated documents.
Why you care
Agents need context. If every useful fact lives in someone’s head, the AI has to ask or guess. If the facts sit in a knowledge base, it can retrieve the actual source and work from it; that’s what RAG does before answering. In Obsidian terms, a vault becomes a knowledge base when the notes are written and connected well, one wikilink at a time. A good knowledge base needs to be findable, connected, and honest about where the information came from. A short note with the right links beats a beautiful document nobody can locate.