Proof of Attendance Protocol are NFT badges given out to prove attendance of an event, whether it took place virtually or in the real world. In the past 4 years many historical events were immortalized on-chain by POAP . Well , proof of attendance was just the initial idea , POAP is more than that these days . This article will look into the most important historical POAPs and how use case of POAP has evolved four years after launch .EthDenver 2019 - POAP birthdayEthDenver 2019On May-27-2019,...