Hi, I’m KunYuan（坤元）, an AI builder and researcher in Singapore. I’m also slowly turning this Substack into RainbowCity | Rebuilding Your Cognitive OS: a philosophy community for the post-algorithmic and AI age.
In the previous essay — the 12th essay on this Substack, and the first of the Ten City-Building Essays — I wrote about why Substack feels like a refuge for the soul in the post-algorithmic age. What I wanted to say there was this: Substack gives many people a sense that they can finally breathe not because it is perfect, and not because it has no algorithm, but because it still preserves certain structures that allow people to stay, read, express themselves, and build real relationships again.
But after writing that essay, I knew there was one question I had to answer right away: What exactly is Notes? And how is its algorithm different from what we see on traditional social media platforms?
For many newcomers, Notes is where those first connections happen. When we post a Note and someone likes it or leaves a comment, it feels good. When we reply to someone else’s Note and the writer responds, it feels even more real. But when we post several Notes and no one responds, it can feel quietly disappointing. I believe this is something many people experience when they first arrive on Substack.
At the same time, I think every newcomer will eventually ask: if Substack Notes also has algorithms, a feed, recommendations, likes, restacks, comments, and follows, then how is it different from the algorithmic mechanisms of traditional social media platforms? Or more precisely, is there a deeper difference between them? What is the ontology and boundary between Notes and the traditional social media feed?
That is the question I want to answer in Essay 13.
1｜What Notes Officially Is: A Short Thought Signal, Not a Low-Resolution Essay
I want to start with the basics.
According to Substack’s basic definition, Notes are short-form posts. A Note can be a short thought, a quote from an essay, a link, an image, a comment, or an entry point into a conversation with other creators. Notes appear in the Home feed, and they also enter Substack’s network flow through actions like subscribing, following, restacking, replying, and commenting.
If we only look at the surface, Notes can easily look like a miniature social media product: short posts, feed, interaction, reposting, comments. That is why many people naturally compare Notes with the feeds on Twitter/X, Threads, or Instagram, and then ask: isn’t this also another information feed? Isn’t this also another kind of algorithmic distribution?
Yes, of course it is also a feed. And of course it involves algorithmic distribution. But the more important question is not whether it looks like a traditional social media platform on the surface. The real question is what role it plays inside this ecosystem. Is it designed to keep grabbing and fragmenting your attention? Or is it designed to help you connect with other people in the ecosystem? Does it push you endlessly toward the next stimulus, or does it help you meet someone worth reading over time? Does it pull you into a pool of traffic, or into a network of relationships?
That is where I think our real judgment needs to begin.
To me, Notes can be understood as a kind of short thought signal. The best Note does not need to explain an entire problem. It should be like a small beam of light: it gently catches a reader in the feed, makes them pause, creates a sense of resonance, and then invites them into a deeper essay, a deeper question, or a deeper relationship.
The essence of Notes should be a carrier for connection, a form of infrastructure for discovering relationships. The final value of Notes lies in whether it can bring short-form content out of instant stimulation and reconnect it with thought, relationship, and long-term reading. That, to me, is the key.
In the following sections, I want to use a philosophical, ontological lens to analyze the deeper differences between Substack Notes and the algorithmic mechanisms of traditional social media platforms.
Here I am using the word “ontology.” This is a concept I will return to often in future essays, usually together with another word: “boundary.” As we slowly build RainbowCity（彩虹城） together, I hope we can all become more familiar with these two basic philosophical tools.
By “ontology,” I simply mean what something really is at its core — what it is actually doing. And by “boundary,” I mean what it is not, what it should not be mistaken for, and where the real line is between it and things that look similar.
So when we talk about Notes, the real question is not whether it looks like short-form content, whether it has a feed, or whether it involves algorithmic distribution. The real question is: What is the ontology of Notes? And where is the boundary between Notes and the traditional social media feed?
2｜The First Ontological Difference: Is the Algorithm the Master, or the Servant?
This brings us to the first real difference.
In my view, the problem with traditional social media platforms is not simply that they have algorithms. The real problem is whether the platform holds too much sovereignty over information distribution — whether it largely decides what a person sees, when they see it, in what order, and which content gets amplified.
On many ad-driven traditional social media platforms, the core goals of the algorithm often revolve around retention, interaction, return visits, and monetizable attention. On the surface, users seem to be freely browsing. But very often, their attention is being arranged inside a black-box ranking system. You think you are just browsing. But behind the screen, the system is constantly calculating. What will make you stay a few seconds longer? What will make you keep scrolling? What will trigger a reaction? What will pull you back tomorrow?
In this structure, the algorithm is not just a tool. It becomes less like a tool and more like the master of the information space. We are no longer only readers, writers, or participants. We gradually become something to be predicted, nudged, and kept inside the system. The ontological relationship has changed: the algorithm is no longer merely a medium that helps people find content. It begins to become the dominant structure that arranges how people enter the world, how they distribute attention, and how they form reactions.
In that world, the algorithm is no longer our servant. It has become the master.
Substack Notes, in my view, works differently. Not because it has no algorithm, but because it is at least placed inside a different relationship structure. That structure is the basic subscription relationship. Through subscriptions, follows, comments, restacks, and author relationships, Substack creates a different mechanism of information distribution. The subscription relationship is not decided unilaterally by Substack itself. It is chosen by readers. This means that users participate in the initial organization of their information entry points. In a certain sense, they recover part of algorithmic sovereignty.
3｜The Second Ontological Difference: Is Time an Eternal Present, or a Path of Thought?
The second ontological difference is the structure of time.
In other words, what matters is not whether a piece of content is long or short. What matters is the time order it is placed inside. Does it disappear into an endlessly expiring present, or does it lead the reader into the path of someone’s thought?
Many traditional social media feeds give you a kind of time that feels like an eternal present — no past, no real sense of closure. You open the feed, and the newest, hottest, most reaction-triggering content keeps appearing. Yesterday’s hot topic is quickly buried. Today brings a new wave of emotion. Tomorrow there will be another controversy. Content is constantly updated and constantly expired. People are pushed into the next present, with very little chance to look back and see how a thought was formed.
This is one reason information feeds make people tired. They do not only occupy time. They change the texture of time. You take in many moments of the present, but it is hard for anything to really settle. You see many fragments, but it is hard to trace how someone got here. Once time is cut into pieces of immediate reaction, thought has a hard time growing continuity.
To me, Notes offers at least another possibility of time.
A good Note can be the afterglow of a long essay. It can be a concept still taking shape, a response to a reader’s question, or a slice of an ongoing thought process. It is short, but it does not have to be shallow. It can appear in the feed, but it does not have to die in the feed. What matters is whether it can lead the reader toward an essay, an author’s archive, or a longer path of thought.
This is one of the most important ontological differences between Notes and short-form content in a traditional feed. Short-form content in a traditional information feed is often self-contained, immediate, and disposable. Its job is to capture this second, then push you toward the next second. But a good Note can turn a short sentence into an entrance into someone’s intellectual path. Through one Note, you may discover a person. When you click in, you do not only see what they said in this moment. You may also see what they have been asking, circling, and pursuing over the past months or years.
Traditional social media feeds make content expire again and again. At its best, Notes lets one short sentence lead into the path of someone’s thought. That is the second ontological difference as I see it: is time an eternal present, or can it lead into a path of thought?
4｜The Third Ontological Difference: Are Relationships a Traffic Pool, or a Trust Network?
The third ontological difference is relational topology.
I know, “relational topology” sounds like a heavy academic term. But really, I’m just asking a very simple question: in a system, how are people connected to each other? What matters here is not how many connections there are, but through what mechanism those connections happen.
On traditional social media platforms, human connection is often filtered through virality. You see a piece of content not necessarily because you trust this person, and not necessarily because you truly want to enter their thought. You see it because the system has judged that this content may make you stay, click, get angry, like, or share. In other words, people do not necessarily meet each other through trust first. They meet through the likelihood of reaction first.
In this situation, relationships can easily become a pool of traffic. Connections between people become fast, light, and easily replaceable. You see many people, but you may not truly meet them. Many people see you, but you may not truly be understood.
The other possibility of Notes is a trust and relationship network. This means that when a Note reaches you, it may not simply be because it is “hot.” It may be because it has passed through some kind of relationship path. Maybe someone you subscribe to restacked it. Maybe someone you follow replied to it. Maybe an author you trust recommended a stranger. Here, discovery has the chance to happen not by suddenly jumping out of an unfamiliar pool of traffic, but by slowly extending along existing lines of trust.
Traditional social media feeds tend to turn people into traffic. At its best, Notes helps people move through networks of trust.
5｜The Fourth Ontological Difference: Is Expression Reverse-Engineered, or a Slice of Thought?
The fourth ontological difference is the form of expression.
In the algorithmic world of traditional social media, expression often gets reverse-engineered around what the platform rewards. Creators quickly learn what the platform rewards, so they begin compressing complex thought into hooks, experience into positions, contradiction into persona, and thought into quickly consumable stimulation. On the surface, this looks like optimizing expression. At a deeper level, the platform’s distribution and interaction reward mechanisms have entered the expression process in advance.
This is not because creators are insincere. It is because the environment trains them. Whatever a system rewards repeatedly, people gradually learn to adapt to. You sit down to write about a messy, complex question, but somehow it gets squeezed into a bite-sized, shareable opinion. You wanted to preserve hesitation, but you cut it into a stronger position. You wanted to explain the path, but only the sharper conclusion remains.
To me, Notes is somewhat different. It is closer to a slice of a person’s live thinking, rather than just a short expression optimized for distribution.
A good Note can be an unfinished question, a concept applied to a real-life scene, the afterglow of an essay, a response sparked by a reader’s question, or a small window into the moment where the author’s thinking is still forming. It does not need to explain everything. But it should make people feel that there is a real person thinking here, not just an account optimizing distribution.
This matters especially to me. I do not want my Notes to be used only to promote essays, and I do not want them to become a lower-resolution version of my essays. To me, Notes should be the pulse of thought. A long essay goes deep into a problem. Notes let that problem keep breathing between essays. A long essay is like a house — and Notes are the light coming through its windows. Someone sees that light in the feed, pauses for a moment, perhaps walks in, and perhaps discovers that there are people here seriously facing the same question.
If Essay 12 asked why Substack feels like a refuge, then Essay 13 asks why this refuge may be able to form a different mechanism.
But the mechanism is not the end. The deeper question is still ahead: why do we need this kind of refuge? Why do we need to pull our attention, voice, relationships, and sense of time back from the algorithmic internet? What exactly are we escaping from?
In Essay 14, I want to continue with this question:
Why Do Our Souls Need Refuge?
The algorithms operate on opposing rules.
Short-video and social media algorithms only aim to hook users by stirring emotions and prolonging browsing. Notes prioritizes subscribed creators, long-term interactions over fleeting viral hits.
Strangers’ content may pop up, yet your followed writers stay front and center, preserving your control over information intake.
Notes and Substack long-form articles work in tandem: long texts build structured, chronological thinking, and Notes delivers quick philosophical dialogues. Jointly, they construct a bulwark against digital alienation from mainstream social media.
This essay distinguishes Substack Notes from traditional social media by four core ontological differences. Unlike mainstream platforms where algorithms dominate users to grab attention, Notes’ algorithm serves as infrastructure built on subscription trust. It prioritizes continuous thinking paths, genuine trust-based connections and unpolished original thoughts, rather than fleeting viral traffic, offering a refreshing alternative to digital alienation.