Crypto Airdrops happen when a project gives out a number of tokens to previous protocol users.

The biggest Airdrops historically have been Uniswap, Apecoin and dYdX.

While some People accumulate single project with multiple wallet, they’re known as Airdrop farmers, they often use hundreds of wallets to interact with same project. On the other hand, projects try to identify and exclude these wallets during allocation.

So, while airdrops can be very lucrative, they are much harder to qualify for these days and even genuine users may get left out.