In the traditional understanding of many people, Ethereum's core positioning has always been the "world computer" or "global settlement layer."
Over the past decade, it has also been responsible for executing smart contracts, hosting DeFi, and supporting NFTs, effectively becoming a programmable financial and application execution layer.
But on March 12, Vitalik Buterin proposed a refreshingly novel perspective—that the crypto industry may have overcomplicated the practical uses of blockchain, and that Ethereum’s most fundamental value might not be the smart contract functionality we’ve always emphasized, but rather an extremely simple primitive:
A cryptographically secure, globally shared "public bulletin board."
Many users may wonder: moving from "Computer" to "Announcement Board"—is this a step backward in functionality, or are there other considerations at play?
I. The "Global Shared Memory" Behind the "Bulletin Board"
The term "public bulletin board," as its name suggests, primarily refers to data availability.
It’s also very simple to understand: imagine a massive bulletin board posted in the center of a city square—anyone can read it, nothing can be removed, and no one can censor it. Here, this bulletin board is global in scope: users worldwide can verify that the data truly exists, even the most powerful governments cannot erase it, and no administrator can prevent you from posting compliant content.
Ultimately, many digital systems today—such as secure online voting and software version control—do not require complex financial transactions, but rather need a censorship-resistant, publicly verifiable space for data publication, which is precisely the long-sought-after "bulletin board" in the field of cryptography:
- Secure voting system. Traditional electronic voting relies on centralized databases, which are vulnerable to tampering. By publishing voting records on Ethereum, anyone can verify the results, while ballot privacy is protected through cryptography.
- Certificate revocation system. A publicly accessible and tamper-proof data source is required for revocation lists of HTTPS certificates and software signing certificates; blockchain is naturally suited for this role;
- Multi-party coordination and governance. In scenarios such as open-source projects, decentralized governance, and community funds, multiple parties need to collaborate without trusting each other—Ethereum can serve as a neutral coordination layer to publish data and verify actions.
These scenarios share a common characteristic: they don’t require Ethereum to “run” anything, only to “remember” something. Vitalik therefore provided a more precise ultimate definition: Ethereum is global shared memory.
Anyone can write, anyone can read, and no one can unilaterally erase it—not any company, not any national government, and not even Vitalik himself.
This positioning also corresponds to a clear technical roadmap: EIP-4844 (Blob Data) in 2024 represents the first expansion of this bulletin board, while PeerDAS (Peer Data Availability Sampling), fully deployed by 2026, increases the board’s “area” by a hundredfold. Ethereum no longer focuses solely on the main chain’s TPS, but instead aims to become the world’s largest and most secure proof-of-storage center—a foundational layer providing globally shared data availability.
II. AI Has Arrived, Making the Public Bulletin Board More Necessary
Once you understand the essence of the "bulletin board," you'll see that the arrival of AI is not two separate things, but two sides of the same coin.
Objectively speaking, the concept of the "bulletin board" is closely related to how AI is currently impacting Web3. Today, an increasing number of people interact with AI more frequently each day than they do with any human being—but with current AI services, everything you ask, when you ask it, and how many times you ask it is tied directly to your real identity.
For example, when you use ChatGPT, you need an email and a credit card; when you invoke the Claude API, your billing records are clear—each prompt leaves a distinct digital footprint.
Therefore, Vitalik and Davide Crapis, Head of AI at the Ethereum Foundation, jointly proposed the ZK API Usage Credits in February 2026, aiming to enable anonymous access to large AI models using zero-knowledge proofs; the logic of the solution is straightforward:
A user deposits funds (e.g., 100 USDC) into a smart contract, which records the deposit on-chain in an encrypted list. Thereafter, each time the AI API is called, the user does not need to reveal their identity—instead, they simply generate a zero-knowledge proof demonstrating, “I am authorized to use this credit limit,” to complete the request.
What does this solution require? A public bulletin board and an openly verifiable, immutable data layer to record "who has how much credit" without recording "who is who."
Meanwhile, the widespread adoption of AI agents has introduced another new challenge: how can these autonomous programs achieve economic collaboration with one another? After all, when one AI agent needs to invoke the services of another, it must make payments, establish trust, and resolve disputes—but it has no bank account, no legal identity, and no centralized platform-verifiable “real-name information.”
Ethereum, as the economic coordination layer for AI agents, provides a natural solution: agents can initiate on-chain transactions, stake collateral, and build verifiable reputation records—all built upon the transparent data layer provided by that “bulletin board.”
Within a broader framework, this relationship between Ethereum and AI is not just complementary but increasingly integrated—as AI capabilities grow stronger, the demands for privacy, verifiability, and decentralization become more essential.
So, Ethereum isn’t competing with AI—it’s becoming the essential infrastructure of the AI era: a public data layer that anyone can write to, anyone can trust, and no one can shut down.
Three: Isn't the narrative around "smart contracts" enough?
In Vitalik Buterin’s vision, future Ethereum users may mostly not be humans, but AI agents.
Therefore, this shift in positioning from the "World Computer" to the "Bulletin Board" may be mistakenly interpreted as lowering expectations, but in fact, this understanding is the opposite.
“The World Computer” is a narrative from an internal perspective, asking, “What can our technology do?” while “The Bulletin Board” is a perspective driven by external needs, asking, “What does the world truly need?”
This may also be due to the group Vitalik met at a cryptography conference—researchers studying voting systems, designers of certification protocols, and developers of privacy tools—who had no interest in blockchain or Ethereum, but whose needs happened to be precisely what Ethereum could provide.
Therefore, I believe Ethereum is indeed becoming more practical step by step, because this is the appropriate stance for a mature technology—no longer trying to define specific use cases, but instead refining itself into a sufficiently reliable infrastructure, waiting for truly needed applications to emerge naturally.
Just as TCP/IP doesn't explain what the internet can do, but without TCP/IP, the internet can do nothing.
From this perspective, this could be seen as Ethereum’s opportunity to reflect inwardly when things don’t go as planned.
After all, the most fundamental and irreplaceable value of blockchain has always been its truth, independent of any individual's will. This means that no matter how fast AI evolves or how blurred the line between reality and illusion becomes, as long as this bulletin board remains, humanity will have a place to preserve "truth."
This, perhaps, is Ethereum's most honest self-definition yet.