An airdrop distributes tokens to addresses meeting criteria the project defines. Because the criteria are chosen rather than discovered, they determine who receives value and what behavior gets rewarded.
The eligibility snapshot is a cutoff
Projects select a block height and evaluate on-chain history as it stood at that point, so activity afterward has no effect on the outcome.
Announcing the height in advance would let anyone qualify immediately, so it is usually disclosed only after the fact, sometimes well after.
The uncertainty is deliberate. It means people who want to qualify must behave as though any moment might be the cutoff, which extends the period of activity the project benefits from.
Criteria are chosen to reward use
Common measures include how many transactions an address made, how long it interacted with the protocol, how much value it moved and whether it participated in governance.
Projects generally weight sustained activity over single large transactions, because the objective is identifying users rather than identifying capital.
Thresholds create cliffs. An address just below a minimum receives nothing while one just above receives a full allocation, which is why exact rules attract intense scrutiny once published.
Filtering out farming is imperfect
Because distributions go to addresses, one person can create many addresses and perform the qualifying actions in each, an approach usually called farming.
Projects respond with clustering analysis, identifying addresses funded from a common source, transacting in identical patterns or moving in synchronized batches.
The analysis produces judgments rather than certainties, and legitimate users with several wallets can be excluded by the same heuristics that catch coordinated farming.
Claim mechanics carry their own design
Most distributions require recipients to claim rather than pushing tokens out, since pushing to many addresses would be expensive and would send tokens to abandoned wallets.
Claims are usually verified against a stored hash summarizing the eligibility list, with each recipient supplying a proof, which keeps the list itself off chain.
Deadlines are common, and unclaimed allocations typically return to a treasury, so a distribution's effective size is smaller than its announced size.
Distribution shapes the market that follows
Recipients did not buy the tokens, so a substantial share of them have no cost basis and no reason to hold beyond expectation of future value.
Projects address this with vesting, staged unlocks or requirements to lock tokens for enhanced allocations, each of which shifts rather than removes the eventual decision.
The structure of an airdrop is therefore a statement about what the project wants its holder base to look like, and reading the criteria reveals that intention more clearly than any announcement does.