PKM vs RAG vs Wiki vs Memory Systems Explained Clearly

The article separates four knowledge layers: PKM, wikis, RAG, and AI memory systems.

PKM is for personal thinking and synthesis; wikis are for shared, maintained documentation.

RAG retrieves external context during generation, while AI memory preserves agent context over time.

Using the wrong layer for the job can lead to stale wikis, weak RAG, and poorly designed AI systems.