Ethereum co-founder Vitalik Buterin ‘vibe-codes’ anonymous billboard demo with onchain moderation on Aztec

We have a massive problem in crypto that nobody likes to talk about. We build these powerful tools for privacy and decentralization, but the moment you open them up to the public, they turn into a dumpster fire of spam, scams, and low-grade garbage. It happens every time. It is the cost of absolute freedom, or so we are told.

Last week, Vitalik Buterin decided to build a toy that might actually point toward a middle ground. He called it 'vibe-coding,' which is basically his way of saying he spent a few hours hacking together a demo to see if a concept actually survives contact with reality. The project is an anonymous digital billboard built on Aztec, and it tries to solve one of the hardest problems in the space: how do you let people post anonymously without letting them ruin the neighborhood?

The Privacy Paradox

If you build an anonymous billboard on a public ledger, you usually get one of two things. You either get a sanitized, censored platform that is no better than a corporate social media feed, or you get a toxic mess that gets shut down by regulators or hosting providers in forty-eight hours. The middle ground is incredibly hard to find because, in a decentralized system, who gets to decide what is 'good' or 'bad'?

Vitalik’s demo uses Aztec’s privacy-preserving tech to allow users to post messages without revealing their identity. But here is the catch: it includes a moderation layer. Now, as a builder, your first instinct might be to recoil at the word 'moderation.' We are here to escape the gatekeepers, right? But Vitalik is looking at this from a functional perspective. If a tool doesn't work for humans, it doesn't matter how pure the math is.

How the 'Vibe' Actually Works

The system he put together uses a few interesting levers. First, it relies on zero-knowledge proofs to ensure that a poster can prove they have the right to post without showing who they are. That is the standard privacy part. The clever bit is the 'censor' role. There is a designated account that has the power to flag or remove content that doesn't fit the 'vibe' of the board.

To make this scale—and to keep the human moderator from losing their mind—he integrated a local Large Language Model (LLM) flagging daemon. Basically, an AI sits in the middle, scanning the incoming anonymous posts. If the AI thinks a post is garbage, it flags it for the human moderator to review. If it passes the vibe check, it stays on the chain.

What is interesting here from a technical standpoint is that the moderation isn't happening on a centralized server in a vacuum. It is baked into the on-chain logic of the demo. It is an experiment in 'soft' governance for ephemeral spaces.

The Problem with LLM Cops

As a founder, you have to be skeptical of anything involving AI moderation. We have all seen how brittle LLMs can be. They are easily tricked by 'jailbreaking' prompts, and they suffer from the bias of their training data. If you let an LLM decide what constitutes a good 'vibe,' you are just outsourcing your censorship to a black box created by a different group of engineers.

Vitalik seems to understand this. His demo isn't suggesting we let GPT-4 run our social protocols. It is suggesting that we can use local, private models to act as a first-line filter. This is a subtle but important distinction. By keeping the model local, you aren't sending your data to a central provider. You are using the tool as a personal assistant for the protocol, not as its master.

Why Builders Should Care

Most of the founders I talk to are obsessed with 'full' decentralization. They want a system that is unstoppable. But unstoppable systems are often unusable for the average person. If you are building a social app, a game, or any platform where people interact, you have to find a way to manage the community.

This demo is a signal that the 'all or nothing' approach to privacy is dying. The next generation of privacy tools will likely include these types of conditional mechanics. You can be anonymous, but only if you play by the rules of the local 'vibe' of the community you are entering. It is essentially digital property rights applied to a shared visual space.

What is missing?

The major missing piece in a 'vibe-coded' world is accountability for the moderator. If the moderator is just a single address, we have just reinvented the moderator role on Reddit or Discord, but with extra steps and higher gas fees. For this to work in a real-world scenario, the moderator role itself needs to be decentralized or rotating.

Imagine a system where the community votes on the 'vibe' parameters, and the AI daemon is updated to reflect those shifting values. That is much harder to build than a simple billboard, but it is the logical conclusion of what Vitalik is testing here.

The Founder's Takeaway

The lesson here isn't about billboards. It’s about the fact that we finally have the tools to build nuanced systems. Aztec and other ZK-platforms allow us to separate identity from behavior. You can prove you are a 'good actor' in a system without giving up your name, your address, or your history.

If you are building in the ZK space, don't just focus on the privacy of the transaction. Focus on the 'vibe' of the interaction. How do you design a system that protects the user but also protects the platform from being high-jacked by the worst 1% of the internet? Vitalik’s weekend project is a reminder that the best tech in the world is useless if it doesn't create an environment where people actually want to spend time.

The future of crypto social isn't just about hiding who you are; it's about proving you're someone who belongs in the room, without having to show your ID at the door.

We are moving away from the era of 'privacy at all costs' and toward an era of 'conditional privacy.' As a builder, that is the most exciting—and terrifying—landscape to navigate. It requires us to be more than just coders; we have to be architects of social norms. And judging by the current state of the internet, we have a lot of work to do.

Read the original at The Block →