Fifteen years ago, the first altcoin Namecoin was launched, directly forking Bitcoin's code. Before its appearance, Bitcoin was the only cryptocurrency in the world. Namecoin introduced several innovations: ◦ Pioneered the merged mining model, allowing miners to mine BTC while simultaneously mining Namecoin with the same computational power—two birds with one stone. This inspired later developments like sidechains and Layer 2 solutions. ◦ Introduced blockchain-based domain names with .bit, serving as an early prototype for Web3 decentralized identity. This later inspired services like ENS. ◦ Demonstrated in practice that blockchain could function as a decentralized database for storing key-value pairs. This influenced the design of state storage in later smart contract platforms.