Personal knowledge management is the intersection between personal information management (e.g., how you remind yourself to complete tasks) and knowledge management (free flow of information within an organisation). It’s about collecting, understanding, and connecting new information with an emphasis on the latter two.

There are few formal PKM systems (but see Zettelkasten) and most people make their own flavour. Mindmaps, notebooks, journaling techniques etc are all forms of PKM.

References

NessLabs - How to take smart notes My PKM Story The Sweet Setup intro on PKM Notes Against Note-Taking Systems How to Take Smart Notes