Airdrop
In short A crypto airdrop is a free distribution of tokens to wallets, usually to reward early users, build a community, or spread out ownership.
An airdrop is when a project sends free tokens to a set of wallets. Recipients might be early users of a protocol, holders of another token, people who completed tasks, or community members. The goal is usually to spread ownership, reward people who helped, or attract attention.
There are two main delivery methods. In a direct drop, the project pushes tokens into eligible wallets. More often, it publishes a list of eligible addresses, commonly as a Merkle root in a claim contract, and each person connects and claims within a deadline. Eligibility is usually based on a snapshot of onchain activity taken at a specific block, such as having swapped, bridged, provided liquidity, or held a token by that date. Uniswap's 2020 airdrop of 400 UNI to every past user is a well-known example of the retroactive model.
Airdrops come in a few common forms. Retroactive drops reward wallets that used a protocol before a snapshot nobody announced. Points programmes let users collect points for swaps, deposits or referrals, converted into tokens later at a rate the team sets. Holder drops go to wallets that held a given token or NFT at a set block, and tap-to-earn games on Telegram convert in-game points once the token launches. In each case the snapshot, the claim and the exchange listing are separate dates, and only the project announces them.
For users, airdrops can be worth real money, which has created a whole practice of farming them by using new protocols in hopes of qualifying. That attracts sybil farmers running hundreds of wallets, so projects increasingly filter them out. Airdropped tokens often see heavy selling right after the claim opens, which can drag the price down quickly.
Airdrops are also one of the most common scam lures. Fake claim sites, unsolicited tokens in your wallet, and messages saying you are eligible often lead to wallet drainers. Only claim through links from the project's official channels, check that the claim transaction does not request broad token approvals, and ignore tokens that appear in your wallet out of nowhere. In many countries airdropped tokens can also be taxable when received.