A crypto airdrop​ ​is​ ​when​ ​a​ ​blockchain project distributes​s ​free​ ​tokens or​ ​coins ​to​ ​the​ crypto ​community.

To​ ​be​ ​a​ ​recipient​ ​of​ ​a crypto ​airdrop often​ ​the​ ​only​ ​requirement​ ​is​ ​that​ ​you​ ​have​ ​coins from the relevant blockchain stored​ ​in​ ​your​ ​wallet. Examples of this format of airdrops are Byteball, Stellar lumens and OmiseGo. These airdrops required you to proof you were the owner of Bitcoins or Ethereums at a certain time ( snapshot) of the blockchain.