What is a crypto airdrop it earn free con?

A​ ​crypto airdrop​ ​is​ ​when​ ​a​ ​blockchain project distribute​s free​ ​tokens or​ ​coins to​ ​the​ crypto ​community.
This can also be done on other blockchains, but Ethereum and Bitcoin are the most used for this airdrop format.

Currently the most commen crypto airdrops require a few simple social media task. These projects use an airdrop as a marketing campaign.