The special thing about the Arbitrum blockchain is its approach to scaling Ethereum using Optimistic Rollups, which allows for faster and cheaper transactions while maintaining Ethereum's security guarantees. Here are some key points:

Optimistic Rollups: Arbitrum uses an optimistic rollup protocol where transactions are processed off-chain in batches, reducing the load on the Ethereum mainnet, which in turn reduces gas fees and increases transaction speed. This means transactions are assumed to be valid unless contested, which is different from other solutions like ZK-rollups that use zero-knowledge proofs to verify transactions immediately.

Lower Fees and Higher Throughput: By moving much of the computation and storage off-chain, Arbitrum significantly reduces the cost of transactions and increases the throughput, making it more practical for applications requiring high transaction volumes like decentralized finance (DeFi) and gaming.

Security: The security model of Arbitrum is based on Ethereum's, using fraud proofs to challenge incorrect transactions, ensuring that the security of transactions is maintained at the level of the Ethereum mainnet.

Governance and Control: Arbitrum provides a governance model where token holders have control over upgradability, can appoint or remove foundation directors, and manage an on-chain treasury, offering unique control mechanisms to the community.


These features make Arbitrum a notable Layer 2 solution for scaling Ethereum, aiming to make blockchain technology more accessible and efficient without compromising on security or decentralization.

Ethereum Compatibility: Arbitrum is designed for high compatibility with Ethereum, allowing developers to use existing Ethereum tools, wallets, and smart contracts, making the transition to using Arbitrum for scaling relatively seamless. This compatibility extends to the execution environment, where Arbitrum's technology stack, known as Nitro, uses a fork of Geth, Ethereum's most widely used implementation, modified for layer 2 functionality.