A crypto airdrop is a promotional event conducted by a cryptocurrency project where tokens or NFTs are distributed to holders of a particular cryptocurrency. These airdrops can vary in value and are often used by development teams to increase awareness, attract users, and reward community members. There are three main types of airdrops: standard/raffle airdrops, which require simple sign-up or registration; bounty airdrops, which involve completing specific tasks such as social media promotion or community engagement; and holder/exclusive airdrops, where tokens are distributed to holders of the project's cryptocurrency without any additional action required. A notable example of an airdrop was the NEO blockchain's distribution of ONT tokens to NEO holders in 2018, which amounted to over $40 million in value. Overall, airdrops serve as a strategy for cryptocurrency projects to incentivize participation and foster community growth.