Token distribution rewarding past actions. Unlike a standard airdrop, where users know upfront what they must do to qualify, the eligibility criteria for a retrodrop are announced only after the fact: the project rewards those who used the product prior to the official token launch or the airdrop announcement. The most prominent example is the 2020 Uniswap retrodrop, where every address that had executed a swap before a specified date received 400 UNI tokens worth approximately $1,200 per wallet at the time.