An “airdrop” is a way to distribute cryptocurrency to the general public by allowing them to have certain tokens or wallets that are on a specific blockchain. This is often done to encourage the holding of tokens and to induce people to join the blockchain network.
Airdrops are usually conducted by requiring that users hold a set amount of tokens in a publicly discoverable wallet at a specified time (snapshot). The snapshot would be used by the token project to distribute the airdrop tokens.
Airdrops can be used to diversify cryptocurrency holdings, increase awareness about the token and receive a dividend (of their existing holdings). Many airdrop campaigns offer simple tasks such as sharing news, referring friends, or downloading an application.