Are those spreading all over around especially in this forum known to be an "airdrop" is considered an airdrop or bounty campaign since some of those are requiring people to fill up some of the forms or need to sign up or follow some social media accounts, etc?
Different airdrops have different requirements and the basic aim of an airdrop is to send some free coins to interested people but they require some work to be done like one may give out coins for just posting your coin address and name while some may ask you to link your social media and this is also done to ensure that participants are not cheating because abusing of an airdrop is common.
you did some task or work to get those coins.
I call them bounty if they require you to fulfill a particular task. Campaigns and airdrops are similar actually but the only difference is that while campaigns have a strict task you need to perform but airdrops are usually only to connect your social accounts or fill a small form and get your coins. Also airdrop coins are fixed but bounty campaigns payment usually varies from user to user based on how well they perform the task given to them.