Personal knowledge management, or PKM, describes an ecosystem of tools and methodologies that help you manage notes. You can think of it as building your own, personal Wikipedia.
In this post I hope to introduce the reader to the "PKM space". It will essentially be a two-step journey. The first step is: motivation. I.e., why would you reach for PKM tools and methodologies to begin with. The second step is: what you get with PKM tools. I.e., how PKMs help. I end this article with some of my recommendations, and begin with a quick note about terminology.
Terminology
There are lots of ways to refer to the "PKM space". Other terminology includes: tools for thought, second brain, knowledge garden, personal knowledge and information management (PKIM), and personal wiki. Advocates for each of these terms will argue that there are differences between them. From my perspective, and for the sake of introducing someone to PKMs, they all seem about the same, and can be considered interchangeable terms.
Motivations
Managing notes is hard
This is a major motivation. Let's look at what makes note management difficult.
Types of notes
There are many different types of notes: journaling notes, creative writing notes, scratchpad notes, notes for processing a particular topic you are unfamiliar with, notes for processing a particular nuance of a topic you are very familiar with, task management, lists, plans, research, reviews, op-ed style hot-takes, etc. All these different types of notes are hard to manage and keep track of.
Location of notes
Notes are often strewn across various mediums: in physical journals, on note taking apps, in cloud document stores, on sticky notes, on websites, etc. All of these different locations for notes can be hard to manage, keep track of, and integrate into each other. Consolidating some of these notes into a single place requires you to chose a single note location you actually like (though you might not "like" any of them), and then transfer all your notes into it. First of all, that might not even be feasible, since some notes might not be exportable, and if they are, they might not be in a transferable format. Second, it's almost certainly a daunting and difficult task that will scale with the number of notes you have. Lastly, there is likely note duplication in the various places that will require reconciliation.
Note utility
It can be hard to rediscover old notes, figure out where to put new notes, quickly grok what's in large notes, or understand/remember why you even created some small notes in the first place.
PKMs are neat
This is a minor motivation. PKMs are cool. A personal wikipedia. A second, external, brain. A knowledge garden. Those just sound neat to me.
Most PKMs will have a graph view of your note collection. It's a big web of notes and connections between them, showing clusters of thoughts. It is the topology of the internet of your own knowledge. Do I find the graph view useful? Nope. Not at all. But is it cool looking? Oh yeah. And that, in and of itself, is a minor motivation.
Anti-motivations, or, why you might not want a PKM
Managing notes is not hard
Perhaps it does not "feel difficult" managing your notes. You might not take a lot, you might have home-grown management strategies already in place, or you might not take a lot of personal notes (and so "group knowledge management" is more your interest).
I know people who have tried PKMs and ultimately abandoned them, reverting to their preferred system. That is totally fine. The goal is to manage your notes well, or really to feel like you are managing them well. If you feel that way, then mission accomplished.
I don't know how I'd use it
"PKMs sound great. I'm interested, but I can't think of a good use-case for it. I don't see how it can be useful for me."
I have sympathy for this perspective because I think it's essentially correct. PKMs are not much more than yet-another-note-taking-app. I had Roam (my first PKM) for years with almost nothing in it. It was practically useless. I only kept it because I thought the idea of a PKM in general was neat. Over the last half decade I've moved to a new PKM (Obsidian) and consolidated notes from across multiple notes locations. With all that fuss and labor and time, I still didn't find it particularly useful.
In fact, only recently have I felt like I've been benefitting from my PKM habits. I have a one-stop-shop for a lifetime of notes. I am, currently, the "future self" I wrote them for, and I appreciate the reminders, tips, etc. They've been useful.
Here's another nice upside: As curiosity goes, I've created thorough webs of notes on obscure topics that would then lay dormant for years. But, not forgotten! After a quick search I can rediscover those notes years later. And, honestly, you remember a lot rereading them. It feels good. It is an example of a long-term joy-reward.
In conclusion, my suggestion for people who feel like they don't know how they'd use a PKM is to experiment. Get a free PKM tool/app and add new notes to it. Don't bother with porting in notes and other time-intensive activities. Get a feel for it. See if it's your cup of tea. I don't think PKMs are particularly world-changing, after all, and bountiful note harvests are far in the future no matter what you do. Make sure you enjoy the journey of seeding notes, the journey of building up your network of knowledge over time.
If you don't enjoy using it, or if you feel it's not providing much value for you, you're right! No drama. To know you have tools like this accessible to you, should you want to use them, is good in and of itself. A tool in a toolbox for a rainy day!
A brief history
People have been attempting to manage notes for a while. The oldest method I'm aware of is zettelkasten which can arguably date itself back to the 16th century. It is a methodology of managing information by adding metadata to notes (for example, tags in the top right corner of index cards). This metadata, amongst other things, refers to other notes within the zettelkasten system of notes.
Another early idea in this space was the Memex, a mechanical device that helped manage personal knowledge. It was an idea popularized by Vannevar Bush in the 1945 Atlantic magazine article As We May Think.
I don't know if a machine like the Memex ever actually existed, however, many things that do exist were inspired by it, including HTML hyperlinks, and backlinks in wikipedia. For example, Tim Berners-Lee mentions the Memex as an inspiration in designing HTML hyperlinks in The World Wide Web: The Past, Present, and Future.
What you get with PKM tools
This section is about what differentiates PKMs from other note taking solutions. That is, what features a PKM offers that normal note taking solutions do not. The three core features I want to talk about is linking (aka, backlinking), discoverability (of notes), and note metadata.
Linking
What I dare say is the universally agreed upon, most important feature, of any PKM tool is: linking (or "backlinks"). That is, the ability for a note to "easily" reference another note. The best examples of this are, as mentioned in #A brief history, HTML hyperlinks and Wikipedia backlinks.
In my preferred PKM tool, Obsidian, you reference other notes via the "Wiki link" syntax which is [[ ... ]]. Inside those double square brackets is the title of another note, which you can navigate to by clicking on it.
Discoverability
Another important feature of PKM tools is the ability to easily discover your notes. As the number of your notes grows you might forget about older notes. They might get lost in the noise of folders and files. For example, I have essentially written the same note twice, forgetting I had already written similar thoughts on a topic years ago. Sometimes those old thoughts are embedded in a long note, sometimes they are in a note that's titled in a way that I'd find odd now. Being able to discover this old content is crucial to good note management.
Search
One core way that PKM tools enable discoverability is through a robust search feature. In general, you will want a fuzzy search that matches titles, content, metadata, etc.
One common way for a note to come about is by you writing about the topic in other, tangential notes first. You will then want to consolidate that information into a new note. Finding all the places you've mentioned that topic previously is something you will want a powerful search function for.
No matter the PKM tool you choose, eventually you will want to spend a bit of time learning about it's search features.
Folder structure
Another way to facilitate note discovery is through a particular folder methodology. If you always know where to put a note, you also always know where to find a note.
I personally avoid folders as much as possible in my own PKM. I have what could be called a "flat" structure where every note is in the root folder. But, at the end of the day, being anti-folder is itself "yet another" folder methodology, so the real takeaway here is to make sure you like the folder constraints of your tool/method.
As a counter-point to my "anti-folder" method, another method that I know some people have and like is the PARA system, which I believe is a method that suggests having a four top-level folders: Projects, Areas, Resources, and Archives.
Metadata
I'm using the term "metadata" as short-hand for all the various ways you can mark or tag your notes, and which is not the note content itself. For example, tagging a note as "#tech" or "#cooking", or attaching timestamps to a note for "created_at", "updated_at", and "published_at". You can tag, flag, alias, create psuedo-folder groupings, and more.
Metadata is powerful. A tool with intuitive metadata features can quickly make the user feel like they have superpowers. The scope is broad regarding what you are capable of doing with metadata. I'll just mention a few. Tags are a way to put the same note in multiple locations. You can think of them almost like having multiple folders for the same note. Aliases are a way to give the same note multiple titles, or, rather, multiple ways of being referenced by other notes. Lastly, metadata can be parsed in many PKMs, allowing you to build plugins that integrate with your PKM and manipulate your notes in clever ways. For example, I wrote a script that parses my note metadata for a "public" boolean to decide which content I put on my website (like this article itself).
My PKM recommendations
If you are comfortable with markdown, I think Obsidian is awesome, and highly recommend it. Other PKM tools I'm somewhat familiar with include Roam and it's open-source competitor Athens, both of which use a block-based content system that I suspect(?) was inspired by Notion. I have heard good things about logseq and zettlr as well. Of all the ones I've just mentioned, I am only really familiar with Roam, Notion, and Obsidian.
If you are partial to strong methodologies, and don't trust going "all in" on particular tools that might not be around in a decade, I have heard good things about the PARA system by Tiago Forte. I have not used it myself, but from what I've read, it seems opinionated (in a good way). The upside of a methodological approach, it seems, is that you can apply it to any tool you want. So, you can turn tools like Google Drive, Microsoft OneNote, Apple Notes, Notion, EverNote, etc., into your own PKM.
Once you have a preferred tool and/or methodology, you will also want to think about workflows. By workflow, I mean something like the "lifecycle" of a note: How do you capture initial ideas? How do you extract notes and highlights from things you've read, heard, or watched? How does that content make its way into your PKM tools?
See My PKM Workflow for a thorough discussion of my approach. An extremely simple example is taking "quick notes" in a note app like Apple Notes, and later porting that note into Obsidian. Apple Notes then acts like an "inbox" for ideas, which get addressed in Obsidian more fully at a later time.
A Knowledge Garden
I think of my process as tending to my knowledge garden. Taking copious notes is inevitably tedious. It takes effort. But, there is joy in the toil when you can keep interesting ideas fresh within your thought-life. It can lead to the creative and enjoyable intermingling of ideas. I think of this tedious "work in progress" as a knowledge garden. My notes are sometimes bad, sometimes they get deleted (or pruned), or barely grow in size. Some of my notes grow strong and generate new notes as my depth of knowledge grows. It's a journey, and I enjoy thinking about the journey, by analogy, as one of cultivation. I'm not trying to impress anyone or reach a certain size or quality. It's like a backyard garden that brings me joy to work on. It is a peaceful place I go to for writing and thinking.
Conclusion
There is joy in taking good notes. In the "PKM space", tools, methodologies, and workflows exist to help you in that endeavour. I'd recommend you to check it out!
You can read about My PKM Workflow to get a sense of what a working PKM setup looks like.
Thanks for reading :D