One of the unique features of blockchains using a public address system is that the current holdings and transaction history of all addresses are publicly available.
It is similar to us knowing the current holdings and transaction history of every stock investor in the world without knowing their identity.
This feature opens up incredible possibilities for profiling addresses and finding patterns in address-level behavior for use in different initiatives, such as coordinating action amongst stakeholders and customer loyalty building.
Another feature of blockchains using a public address system is that anyone can send any digital asset to a public address.
Marketing firms have been using analytics on the history of an address together with the ability to send assets to drive engagement for new projects or bring attention to new initiatives by existing projects.
This sending of assets to targetted public addresses to increase engagement or reward early adopters is known as an airdrop.