Personal Knowledge Management Systems: 6 Ways To Get Started

One of the best ways to think about a personal knowledge management system is to view it as your second brain. It doesn’t just store the information you’ve read, heard, or watched, but it also helps you to connect the dots between those individual pieces of information. It contains the sum of your personal knowledge, but, at the same time, it is also a pathway for using that knowledge in practice, and can help to generate new insights.

Any person who tries to learn something can benefit from using such a system. It helps us to remember – or at least not to forget things. It allows us to go back and view the notes we took in the past. It summarizes and synthesizes our knowledge. And finally, it helps us to think more clearly and come up with new ideas.

So what exactly is a personal knowledge management system?

Well, before looking at the different systems and tools themselves it’s important to understand a few things. First, why and how note-taking forms the basis of a personal knowledge management system. Second, what exactly personal knowledge management means. And thirdly, how such a system can help transform basic facts or information to something that can actually be applied.

When it comes to choosing a personal knowledge management solution you need to make a decision on the overall strategy you want to take. This requires some upfront choices about how you want to approach knowledge management, and what your personal preferences are. While you can always adjust tactics for note-taking and knowledge management, changing the overall system and strategy is more tricky and time-consuming – so it’s best to put some thought into it before you get started.

Why you should take notes

At the core of any personal knowledge management system are notes, the things we write down when faced with new information, data or ideas. Most people view note-taking as something we do to help recall information later on, and while this is true, it’s also incomplete. Notes are also essential in personal knowledge management to connect separate pieces of information, and to ‘create’ knowledge and ideas (and to start using them).

So what happens if we don’t take notes? Well, for a start it means being exposed to information only superficially; in one ear and out the other. Of course, even if you don’t take notes, you might remember some of what you’ve read, but chances are you will forget most of it relatively fast. And, more importantly, even if you do remember something, it’s not going to be integrated into your existing web of knowledge.

Most people probably understand the importance of note-taking. If you have an office job there’s a good chance you already take notes, since it’s essential to record what was discussed and what the action points are. But this is note-taking on a very basic level: it’s action-oriented, and usually doesn’t contribute to higher-level ideas.

Not many people take notes in their personal lives, even though it can be infinitely more powerful there. Just think about all the new pieces of information that we deliberately seek out – in the form of courses, books, podcasts, or documentaries – that help us to learn and grow. What if we could be more effective with that knowledge and apply it in a better way?

What is personal knowledge management?

Taking notes is the basis of personal knowledge management, but it’s not the only step. Wikipedia defines personal knowledge management as “a collection of processes that a person uses to gather, classify, store, search, retrieve and share knowledge in their daily activities”. Which, to be honest, is quite a dry definition.

Essentially personal knowledge management consists of three activities:

  1. Capturing and recording information (i.e. note-taking)
  2. Management of that information – meaning: classifying, summarizing, synthesizing, et cetera.
  3. Using that information; output, creation and sharing.

Or, an alternative way to look at it, is to use Harold Jarche’s seeking-sensing-sharing framework:

  • Seeking is “finding things out and keeping up to date.”
  • Sensing is “how we personalize information and use it. Sensing includes reflection and putting into practice what we have learned.”
  • Sharing is “exchanging resources, ideas, and experiences.”

So personal knowledge management is a process in which you capture information, collected from a wide range of sources, and transform it into something useful. Maybe that usefulness is not visible on the short-term, but as long as it’s recorded and managed properly it can always be ‘rediscovered’ in the future.

The last step of personal knowledge management is always usage or creation. Just collecting information is not the end goal; it’s about using it to remind yourself, to create something with it, or to share it with others.

That, in short, is the beauty of a personal knowledge management system. Normally when we read or learn something we tend to forget it quickly – which obviously is a waste of time and effort. But, if we take the small additional step to record information or the lessons learned into a system that we can easily refer back to, it will always be there waiting for us.

Data, information, knowledge & wisdom

The question at this point is: how do we transform these notes and information into knowledge? Into something more than just the sum of its part? And how can it lead to application in practice? Collecting notes and information might be the first step, but if you stop there it remains just that – isolated and unconnected facts.

One way to answer that is to look at the DIKW pyramid – data, information, knowledge, and wisdom. This pyramid shows why bits of data and information are not valuable by themselves, and that we need to actively work to transform them into something useful.

The DIKW Pyramid

At the base of the pyramid there’s data; the raw facts, stimuli or observations that are not very useful by themselves.

Information is the next level up and consists of refined or inferred data. It’s now in a useful form, maybe it answers basic questions (e.g. who, why, how), or maybe it gives a description or a story. In a way, you could say that information is data with a purpose.

Knowledge is one level higher still, and is essentially organized information. It’s a synthesis or conceptualization of different pieces of information that were collected. Knowledge is what we learn and remember.

Wisdom is highest level of the pyramid, and usually has the vaguest definition. One way to think about wisdom is to see it as understanding, or as integrated or applied knowledge. It’s not just knowing the ‘what’, but also the ‘why’ and ‘how’ and ‘when’ to apply knowledge. In terms of personal knowledge management it is also linked to the creation and sharing from the above frameworks.

The DIKW pyramid is a bit deceptive though; the shape implies that each level up is a refinement of the previous level. Information is refined data, knowledge is refined information, and wisdom is refined knowledge – but this is false. There is a clear gap between data and information at the bottom, and knowledge and wisdom at the top.

Model ≠ Reality

While it is true that the lower levels of the pyramid are about collection and refinement, the higher levels of the pyramid are about learning, creation, and about serendipity – about being curious, having luck, and synthesizing knowledge and wisdom. It’s an active act, versus a more passive one at the bottom of the pyramid.

As David Weinberger writes: “knowledge is not a result merely of filtering or algorithms. It results from a far more complex process that is social, goal-driven, contextual, and culturally-bound. We get to knowledge — especially “actionable” knowledge — by having desires and curiosity, through plotting and play, by being wrong more often than right, by talking with others and forming social bonds, by applying methods and then backing away from them, by calculation and serendipity, by rationality and intuition, by institutional processes and social roles.”

And this is exactly where personal knowledge management systems can help. We can collect data and information (a more passive process), and on the whole it adds little value. But as soon as we start adding, integrating and linking pieces of data and information together, we can start to create knowledge and wisdom (an active process). Doing this also allows for synthesis, building your own narratives, finding your own conclusions, and – as the final step of personal knowledge management – creating something and sharing it.

That might still sound a bit vague, but once we start looking at the different personal knowledge management system it hopefully becomes more clear.

Personal knowledge systems and tools

As we saw earlier, a personal knowledge management system essentially aims to do two things: 1) store and manage the information you’ve collected, and 2) facilitate the higher-level process of synthesis and creation. This facilitation is done, for example, by linking topics or themes together or by making it easy to ‘rediscover’ old notes or thoughts.

The good (or bad) news is that there are many different systems and tools that you can pick from – good in that it there are different options depending on what you want, and bad because it takes a bit of effort to pick the right system to get started.

The details of how you manage information and knowledge can always be filled in later, but the system itself is harder to change. It has a certain lock-in effect: the fact that you’re using it, and that it stores all your information, makes it more difficult to change it later on.

So spend some time upfront to think about how you take notes, how you want to manage and curate information, and – in general – what your overall approach to knowledge management is going to be. Paper or digital?, notebooks or index cards?, note-taking apps or specialized software?, et cetera.

In order to help with the below overview shows the most common personal knowledge management systems and their advantages and disadvantages.

1) Commonplace books

Photo of a commonplace book from the mid 17th century.
An example of a classical commonplace book from the 17th century.
(Photo: Beinecke Flickr Laboratory)

What is it?

Commonplace books are arguably the oldest form of a personal knowledge management system. They are also relatively simple: “commonplacing” essentially means recording any interesting bits of information, facts, quotes, or ideas into a notebook.

Some people might treat a commonplace book more as a diary, others like a collection of personal wisdom, and others yet as a simple compilation of notes on a specific topic. It was a popular solution throughout history, and a wide range of people used it: from Marcus Aurelius to Leonardo da Vinci, and from Ralph Waldo Emerson to Isaac Newton, for example.

Overall, it’s an easy system to get started with since all it requires is a notebook and a pen. But this simple set-up also has distinct disadvantages. For a start, it’s relatively difficult to find or re-encounter information again. It’s not searchable, usually not sorted thematically, and because of the free-form writing, information is also highly distributed throughout the notebook.


  • Simple, easy to set up and to get started.
  • Cheap – you just need a notebook and a pen.
  • There’s a long tradition of “commonplacing”, which indicates there must be some value in the method.


  • In a way, it’s a graveyard of information and ideas – things are recorded but it’s hard to find them again, especially in a free-form structure.
  • Highly distributed – not organized by topic – unless you choose to do separate commonplace books per subject. This makes stumbling on previous thoughts or notes difficult, even though this is one of the goals and advantages of a personal knowledge management system
  • It requires a lot of discipline. Not just to take notes, and write them down, but also to find them again and to keep revisiting them.
  • Not searchable (obviously).
  • Paper-based, which means it’s easy to destroy or lose.

2) Index card system

Ryan Holiday’s index card system (Image from his article on this system).

What is it?

An index card system is quite similar to a commonplace book, but with a few significant upsides. As with a commonplace book information is recorded on paper, but instead of using a notebook, every note gets its own separate index card.

This has a few advantages: it’s easy to make it thematic, to organize notes by topic, and to find – and rediscover – information again. It’s no surprise that it’s a system that researchers and writers love. Ryan Holiday documented his index card system in a good article, and credits the setup to Robert Greene who uses a similar system.

Robert Greene’s system, showing his research for a new book.

Even though you can see it as a variation of a commonplace book, it’s a lot more flexible and practical – it’s easy to select the notes on a certain theme you want to review.


• Organized thematically, so relatively easy to find and reuse notes.
• Still easy to get started.
• Some people prefer physical notes over digital ones when researching or writing, since it’s easy to (re)arrange, see patterns, and shift things around.


• While thematic, the themes will need to define beforehand and it takes a bit of effort to change it or adjust it later on.
• Requires more investment than just notebooks: index cards will have to be purchased continually, and at some point some organizers would help as well.
• Many of the downsides of the classical commonplace book still remain: not searchable, the risks of a paper-based system, not very intuitive.

3) Zettelkasten

Examples notes from Niklas Luhmann's Zettelkasten method.
Example notes from Luhmann’s Zettelkasten method (from: Universität Bielefeld)

What is it?

The Zettelkasten method is a variation of the index card system and has a number of unique benefits, so it’s worth to discuss it as a separate category.

This method originates with Niklas Luhmann, a prolific professor of sociology. In many ways it works similarly to an index card system described earlier. You read, find pieces of information, and then convert them into notes.

The difference with a traditional index card system lies in the organization of the notes. In a Zettelkasten system the key is not to think about predefined topics or themes, but to look at entry points. As Sönke Ahrens puts in How to Take Smart Notes:

“In the old system, the question is: Under which topic do I store this note? In the new system, the question is: In which context will I want to stumble on it again?”

So rather than fitting the notes to predefined topics, use the natural accumulation of clusters of notes to create them. This might seem like a small semantic difference, but it really is not. At the start of setting up a personal knowledge management system it’s difficult to see what will hold our interests over time. Maybe we’ll start exploring different areas, or start reading more widely than we do now. But all of this means that we need to maintain a certain flexibility when it comes to the organization of notes.

The Zettelkasten method, while very similar to the index card system, helps us do that. There’s no predefined rigid structure, and instead we let our own curiosity develop topics. Over time, the accumulation of these “knowledge clusters” shows us where our interests and intellectual curiosity lie. And, in turn, this accumulation of notes in clusters makes it easy to find them and use them.

Simple schematic of a Zettelkasten organisation.
A simple schematic of how a Zettelkasten system can be organized. Every note, or cluster of information, can be branched off to further levels, allowing for accumulation of notes (our “interests”) on lower levels and helping to create new entry points.


  • Flexible.
  • Allows for natural accumulation of topics and themes over time, no rigid structures.
  • Quite intuitive, able to stumble upon previous ‘clusters’ of knowledge.


  • Although it’s more intuitive, it’s not searchable. So finding that one needle in the haystack will still be difficult.
  • Requires a bit more investment than just notebooks: index cards will have to be purchased continually, and at some point some organizers would help as well.
  • Still paper-based – with all the inherent downsides.

4) Note-taking apps

What is it?

Another solution for a personal knowledge management system are the popular note-taking apps, such as Evernote, OneNote, Notion, and countless others. (It does feel a bit unfair to put Notion in the same category as other note-taking apps, since it has a low of great features, but when it comes to knowledge management it fits better here.) These apps are easy to use and easy to set up and so they might be an obvious solution – but not necessarily always be the best one.

One thing to take into account is that most of these apps are silo-based: notes live in notebooks, and those notebooks are organized by topic. It’s hierarchy-based and so you still need to decide how to organize topics at the start. And while it is easier to change the hierarchies down the road compared to paper-based systems, it still is a hassle to do so.

Note-taking apps are (deceptively) simple and easy to use – but in reality it requires a bit of thought to manage it properly.


  • Easy to set-up and use.
  • Available on both computers and phones, so always accessible.
  • Integrations with services such as Kindle, Readwise, and Instapaper, which makes importing notes easy.
  • Cloud-based, low risk of losing information.
  • Searchable.


  • It can be a bit too easy to store information sometimes. It’s not about the quantity but about the quality and usability of notes. Note-taking apps make it very easy to record things and so the risk is that we don’t spend enough time to think about what exactly we want to record. This is all the more true when copy-pasting information rather than summarizing it.
  • Silo-based, as described earlier.

5) Personal wiki’s

What is it?

Personal wiki’s are a bit different than the other solutions on this list. They essentially function like a personal Wikipedia that you develop on your own. Every note, article, or idea has a separate URL – so every note functions as a webpage. When creating these webpages you can then start to link them together, meaning they are easy to navigate to and from, and, in turn, this also allows you to link ideas, create relationships between topics, and rediscover previously made notes.

In a way you could describe personal wiki’s as building your own personal knowledge website. This does not necessarily mean it has to be public though. These wiki’s can also be private and they can even be self-hosted if you want to be fully in control. If you do host it publicly then it’s easy to share with others and to “learn in public,” but most people would probably prefer to keep it private.

One of the most popular personal wiki applications is TiddlyWiki, and that would be a good place to start if you’re interested in building a personal knowledge management system this way.


  • Highly customizable.
  • Hosted on a server, so low risk of losing content.
  • Easy to link topics and ideas together.
  • Searchable.
  • Possible to make it public and to share it with others.


  • Takes a considerate amount of time to set up.
  • Not for everyone, some tech savviness required.
  • Time consuming – creating notes in a note-taking app is a lot quicker than creating a webpage on a personal wiki.

6) Specialized software

What is it?

Over the last few years there have been quite a few developments in specialized personal knowledge management software. There are a number applications worth talking about that fit under this umbrella, and they are all designed to be used as a “second brain,” as a digital commonplace book, or for a digital Zettelkasten method.

While there are different software packages that fit in this category, there are three that stand out:

1) Zettlr, an open source digital tool created for the Zettelkasten method.

2) Roam Research, recently launched and already enormously popular. Roam is a personal knowledge management tool that is completely free flowing and has a very powerful tagging and linking system. Every word, sentence, or note can easily be made into a link – and every link you create is simultaneously a note. This makes it simple to synthesize information, rediscover older notes, and start organizing for output. (If that sounds vague, see here for a longer explanation.)

3) Obsidian, which shares some similarities with Roam Research in that it’s also a personal knowledge management tool that has a free-flow structure and a powerful tagging system. Currently, it’s free for personal usage and also locally hosted – so if you don’t like the cloud-based system of Roam, and want to make sure you can always access your notes, this would be a good alternative.


  • Specifically designed for personal knowledge management.
  • Powerful tagging and linking systems.
  • Intuitive, easy to rediscover notes and topics.


  • Requires some time investing to learn the ins and outs of each program.
  • These programs are relatively new, and Roam Research and Obsidian are both still in development – so unclear how sustainable these programs will be on the long run.


These are the six main options when it comes to personal knowledge management systems: commonplace books, an index card system, the Zettelkasten method, note-taking applications, personal wiki’s, and, finally, specialized software.

Now the question is: which one to choose? The answer to that will completely depend on you and your own preferences – paper-based or digital?, specialized software or not? – and what you intend to do with this system.

In the end though, the exact system doesn’t matter that much; all of the above systems have advantages and disadvantages, but people have been using all of them successfully for personal knowledge management.

So pick a strategy and stick with it, because most of the benefits are reached by consistently using a personal knowledge management system. What you choose might not be the best one subjectively-speaking, but you can get at least 90% of benefits by picking any of the above solutions. The rest? That’s just optimization.

Pyramid Vector from Vecteezy.

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