Gemini Notebook (formerly NotebookLM) has rolled out Collections, a new way to organize your notebooks into groups. Think of it less like a rigid filing cabinet and more like photo albums or music playlists: there are no strict folders, and a single notebook can belong to several collections at once. If you'd rather not bother with any of this, you can keep everything in the default "My Notebooks" tab, just like before.
It's a small feature, but a telling one. When you only have five notebooks, organization doesn't matter much. But once you start using the tool seriously, with a separate notebook for every project and client, things pile up fast. A month in, you're left with a digital junk drawer where finding what you need takes longer than actually reading it.
The playlist logic makes a lot more sense to me than the folder logic. A folder forces you to pick exactly one home for a file, and you end up second-guessing yourself every time: does this note belong under the client, or under the technology? Collections remove that friction entirely, you just file it under both. A single notebook about an AI-driven sales funnel can comfortably live in both "Client N" and "Article Drafts" at the same time.
I made this same shift in my own workflow a while ago: one piece of content, many contexts where it can resurface when needed.
A practical tip: don't rush to create dozens of collections right away. Start with three or four based on how you actually work, for example "in progress," "reference material," and "to read later," and sort your notebooks into those. Once one of them grows too large, that's the moment to split it further.
This kind of flexible tagging system reflects a broader shift in how knowledge tools are evolving: away from rigid hierarchies and toward fluid, overlapping structures that match how people actually think and work.