Dai is not a standalone cryptocurrency; it is a stablecoin that operates on the Ethereum blockchain. Stablecoins are designed to minimize price volatility by pegging their value to a reserve asset, typically a fiat currency like the US dollar. Dai, specifically, is pegged to the value of the US dollar.

Dai is maintained and governed by a decentralized autonomous organization (DAO) called MakerDAO. The MakerDAO system uses smart contracts on the Ethereum blockchain to ensure the stability of Dai. The stability of Dai is achieved through a combination of collateralized debt positions (CDPs) and a system of incentives.

Users can obtain Dai by locking up Ethereum (ETH) as collateral in a CDP and generating new Dai against it. This process is known as "minting" Dai. When a user wants to redeem their Dai, they must return the corresponding amount of Dai to the system and receive back their locked-up ETH. This mechanism helps to maintain the stability of Dai's value.

Since Dai is an ERC-20 token built on the Ethereum blockchain, it can be stored in any Ethereum-compatible wallet. It can also be freely transferred and traded on various decentralized exchanges.

It's worth noting that the information I provided is accurate as of my last knowledge update in September 2021. It's always a good idea to verify the latest developments and updates about Dai by referring to official sources and staying up to date with the latest news.