If you treat NotebookLM like a full-blown second brain, you’re setting yourself up for frustration. It’s powerful, clever, and genuinely useful—but using it as your primary personal knowledge management system is a mistake many people are quietly discovering the hard way.
But here’s where it gets controversial: the problem isn’t that NotebookLM is “bad.” It’s that people are expecting it to do a job it was never really designed to handle.
Mahnoor, a dedicated technology writer and Computer Science student, lives and breathes tech—from late-night debugging sessions to staying up for live product launches. Her work has appeared across several well-known tech sites, including XDA’s sister publications and other major outlets, which gives her a front-row seat to how tools like NotebookLM actually get used in the real world. Drawing from that experience, she’s come to a clear conclusion: NotebookLM shines as a research companion, not as the core of your long-term knowledge system.
NotebookLM is a research ally, not a second brain
Google promotes NotebookLM as an “AI-powered research partner,” and that description is surprisingly accurate. It’s fantastic for tasks like prepping for university exams, picking up a new programming language, or even refining something as everyday as your coffee brewing technique. All of these jobs share a common thread: you’re diving into specific sources, asking questions, and extracting insight—classic research behavior.
And this is the part most people miss: just because you can use NotebookLM in many different ways doesn’t automatically turn it into a robust personal knowledge management (PKM) platform. A PKM system isn’t just about reading or exploring; it’s about building a durable, interconnected body of knowledge that evolves with you over months and years.
What a real PKM system actually does
Before declaring any tool your “second brain,” it helps to get clear on what personal knowledge management really means. A PKM system is more than a storage space for random notes and documents. It’s the overall process and structure you rely on to:
- Capture information from different places.
- Organize it in a way that makes sense to you.
- Track it over time as your understanding grows.
- Quickly retrieve and re-use it when you need it.
Tools like Notion and Obsidian are designed from the ground up with this mission in mind. They usually include:
- Flexible organizational structures (pages, databases, folders, links, tags).
- Ways to connect ideas across topics and over time.
- Features that help your knowledge base keep growing instead of collapsing into chaos.
NotebookLM doesn’t really operate at this level. It helps you explore the information you feed into it, but it doesn’t provide a complete, long-term framework for managing your ideas.
Why NotebookLM struggles to connect your ideas
One of the biggest reasons people try to use NotebookLM as a PKM tool is its ability to spot links between concepts. The Mind Map feature, for example, can surface relationships inside a set of documents in a way that feels almost magical. Ask it questions about your uploaded sources, and it can generate grounded, well-structured answers that highlight patterns you may not have noticed on your own.
But here’s the catch: all of this linking is confined to the specific sources you’ve uploaded into a single notebook at a time. The connections it makes are internal and linear—it’s finding relationships within the boundaries of your current document set, not across your entire knowledge universe.
Compare that to something like Obsidian’s graph view. There, every note you create becomes a node in a constantly evolving map, with links bridging ideas across projects, themes, and even years of work. Over time, your notes form a web of thinking that mirrors how your brain actually develops understanding. NotebookLM’s Mind Maps, in contrast, are more like clever snapshots of one dataset at a time.
This is where the tension really shows. If you want a tool that lets your ideas talk to each other across contexts—across different projects, subjects, and phases of your life—NotebookLM will hit a hard ceiling. The moment your documents stop, the connections stop. That’s fine for targeted research, but not for a personal knowledge system meant to grow with you.
NotebookLM isn’t a true note-taking app
Despite the word “Notebook” in its name, NotebookLM doesn’t behave like a traditional note-taking tool. You can technically create notes inside a notebook, but those notes feel more like quick annotations or scratchpads tied to your current research rather than building blocks for a long-term thinking system.
A genuine note-taking or PKM app usually lets you:
- Structure notes into folders, spaces, or databases.
- Tag and link notes to show how ideas relate.
- Gain an overview of everything you’ve captured so far.
NotebookLM, as it currently stands, offers almost none of that. If you jot something down, it lives inside a specific notebook, and you have to go back into that exact notebook to find it again. There’s no unified view of all your notes, no way to visually or structurally connect them across notebooks, and no serious organizational backbone.
And this is the part most people underestimate: without meaningful structure and cross-linking, your notes become trapped in isolated silos. They’re helpful in the moment but don’t easily contribute to a long-term “knowledge graph” of your life and work.
Your knowledge is trapped in NotebookLM’s ecosystem
Here’s another uncomfortable truth: using NotebookLM as your main PKM tool makes you highly dependent on Google’s platform and decisions. With apps like Obsidian, your notes are typically stored as plain text or Markdown files directly on your device. That means you can back them up anywhere, open them with different editors, and keep them accessible even if the original app disappears.
NotebookLM works very differently. Your work largely lives inside the service. If Google changes the product, limits access, or shuts it down entirely, your ability to retrieve and reuse what you’ve built could be severely affected.
Yes, there are some partial workarounds. You can manually copy content out of your conversations or notes, and there are browser extensions that help you export certain pieces into formats like PDF. But notice how fragile that is: there’s no simple, one-click option to export your entire knowledge base into an open, future-proof format.
So here’s the provocative question: do you really want years of your thinking to depend on whether a single experimental product stays alive and unchanged?
The smarter move: pair NotebookLM with a real PKM
None of this means you should stop using NotebookLM altogether. In fact, it can be an amazing partner when it’s used for what it does best: analyzing your sources, surfacing connections within a defined dataset, summarizing complex material, and helping you explore ideas more quickly.
The key shift is in how you position it in your workflow:
- Let a real PKM system (like Notion, Obsidian, or any other robust tool) be the home base where your long-term notes, ideas, and projects live.
- Use NotebookLM as a powerful assistant sitting next to that system, helping you research, synthesize, and experiment with information.
- When NotebookLM helps you uncover valuable insights, capture and structure those insights back in your PKM so they become part of your lasting knowledge base.
This hybrid approach lets you enjoy NotebookLM’s strengths—its analysis, summarization, and connection-finding—without sacrificing the stability, flexibility, and ownership that a proper PKM provides.
Now it’s your turn
Here’s the bold question that might stir some debate: Is relying on NotebookLM as your main knowledge hub actually convenient—or is it a risky shortcut that will cost you later?
- Do you currently use NotebookLM as your primary note system or “second brain”?
- Have you run into limitations with organizing, exporting, or connecting ideas over time?
- Do you think the convenience of AI tools outweighs the risk of vendor lock-in and weaker structure?
Share your take—especially if you disagree. Should people keep trying to bend NotebookLM into a PKM, or is it time to accept that it’s a brilliant assistant, not the main brain?
