They can be that, or they can be useless tokens used be scammers. Or they can be good coins like Byteball, Bitcore, and DeepOnion that offer airdrops. That is how they can be adminstered, although every group has a different requirement. Airdrop in the purest form is filling out information and getting coins or tokens. This is the least profitable though and that is why scammers use that method on tokens. It is easy and cheap and people will get involved if they get free tokens. Better airdrops in my opinion are in the form of coins, and they give you a % based on how much you are hodling.