The definition, word by word
A clear definition comes from Stephen Davies's 2011 article Still Building the Memex. He calls a PKB "an electronic tool through which an individual can express, capture, and later retrieve the personal knowledge he or she has acquired," then takes the three words of the name one at a time.
| Word | What Davies means | In practice |
|---|---|---|
| Personal | Intended for private use and tailored to one person, holding relationships and observations its owner sees | Your own categories and reactions, written for you |
| Knowledge | The select knowledge you learned from sources, kept apart from the pile of sources themselves | A short entry per idea, with the source attached |
| Base | Kept for the long haul, searchable and browsable, one integrated whole | One place you search for everything you learned |
The knowledge part does most of the work. Davies writes that a PKB exists "to preserve the select knowledge that one has learned from those sources," which leaves out most of what you merely came across. A folder of everything you bookmarked passes the personal test and fails this one.
Where the idea comes from
Davies's title points back to Vannevar Bush's essay As We May Think, published in The Atlantic in July 1945. Bush imagined a desk he called the memex: "A memex is a device in which an individual stores all his books, records, and communications, and which is mechanized so that it may be consulted with exceeding speed and flexibility." He called it "an enlarged intimate supplement to his memory."
The essential feature, Bush wrote, was linking one item to another: "The process of tying two items together is the important thing." Eighty years on, storage is cheap and search is instant. The hard part is still the one Davies points at: deciding what you learned and writing it down in a form you will find again.
What goes in, and what stays out
- Ideas you learned and expect to reuse, written short enough to reread in a minute.
- The source of each idea, so you can check it, quote it or credit it later.
- Your reaction: where you disagree, or how the idea applies to your work.
- Decisions you made and the reasoning behind them.
Tasks, appointments, email and the full text of things you might read someday all have better homes. Inside a knowledge base they bury the entries you will actually come back to.
Three habits that keep it useful
- Write it smaller than the source. One idea per entry is easier to find, link and reuse than a page that mixes five.
- Keep the source attached. A claim without a source is hard to trust a year later, including your own summary of it.
- Come back to it. Entries you never reopen fade along with your memory of them, and a review on a schedule is what keeps both alive.
The input most knowledge bases leave out
Much of what people learn now arrives as posts: a YouTube explainer, a Reel about money, a LinkedIn post about hiring. Each platform has its own way to save a post, and each keeps its own list. Instagram, for example, lets you sort saved posts into collections, and its 2017 announcement says they are private: "only you can see them."
In Davies's terms a saved list sits on the information side. It keeps the sources and none of what you learned from them, and it splits a year of learning into one pile per app, which breaks the base part of the definition as well.
How scrollandlearn fits the definition
scrollandlearn is a web app that builds a PKB from links. You paste a link to a public post from one of 15+ platforms, such as Instagram, TikTok, YouTube, Reddit or LinkedIn, and it comes back as a lesson with the link to the original and the creator's handle.
Automate the transfer
Saving works when the money moves on payday, before you can spend it.
Key points
- Move money on payday, before it sits in the account you spend from.
- Start at a percentage you will not resent, then raise it with each pay increase.
- Keep the investing account separate from the account with the card attached.
- Review the amount twice a year rather than every month.
Try this
Set a standing transfer for the day after payday.
Remember this
Saving fails at the monthly decision, so remove the decision.
In the quiz
When should the savings transfer happen, and why then?
Filed under Money habits
The example above illustrates the lesson a YouTube video about saving money becomes; it shows the format and is not financial advice.
| Davies's part | How scrollandlearn handles it | Where it falls short |
|---|---|---|
| Personal | Private by default, nobody sees your library but you; My takeaway holds up to 500 characters in your own words | No shared library or team space, if you want a shared base |
| Knowledge | A core idea, key points and a marked Remember this sentence per post, Try this when the post suggests an action, and for a video the transcript: what is said on TikTok, Instagram or Facebook, the captions on YouTube | Links work only for posts from the supported platforms and LinkedIn articles; other web articles go in through the browser extension, in Firefox today and soon in other browsers |
| Base | One library across platforms, topics formed on their own, search across titles, key points, takeaways, topics, creators and the words of transcripts, and related lessons under a lesson and under each search | Export downloads the lessons as Markdown, CSV or JSON, not their transcripts, and nothing syncs |
The last row matters for Davies's ideal of a base that outlasts any one tool. Export lessons downloads your lessons as Markdown, CSV or JSON, so they can outlast the app, but without their transcripts and without a sync. If you want everything in one portable archive, use scrollandlearn for the posts you learn from and a notes tool for the rest.
Frequently asked questions
- Is a personal knowledge base the same as a second brain?
- A second brain is one way to build a PKB: Tiago Forte's method with the CODE steps and the PARA folders. Personal knowledge base is the general term, and it does not prescribe a method.
- What is the difference between a PKB and a note-taking app?
- A note-taking app is where you write. A PKB is the collection you keep for finding and reusing what you learned, and it can live in a note app, a database or a dedicated tool.
- How big should a personal knowledge base be?
- There is no target size. Davies stresses keeping the select knowledge you learned, so an entry you would never look for again is a candidate to delete.
- Does scrollandlearn search inside transcripts?
- Yes, for exact words. Search finds lessons by title, key points, core idea, Try this, Remember this, your takeaway, topic and creator handle, and also lessons whose transcript holds every word you typed, with the passage around the first one. Transcripts have no timestamps, so it does not jump to a moment in the video.
- Is my scrollandlearn library private?
- Yes. It is private by default and nobody sees it but you. There is no public sharing and no team space.
