Actually, I don't believe airdrop. It likes scam. Most tokens from airdrop are useless. I prefer ICOs than airdrop.
I kinda feel the same now, last I applied for +10 airdrops and 9 out of ten were a waste of time, I was doing free marketing on social networks but never received anything. Would be good to get some feedback what criteria needs to be met so the project is legit. I don't sign up if I don't find the project interesting and skip the ones who just have google forms without any context, but still the outcome is so marginal.
Sometimes they are not worth anything but you get swiftcoin instantly. I had joined and they gave me 75 coins very fast my friends also did that and they got the coins also.
It is just giving your mail and your adress they give you the coin i know it is maybe not worth it but its instant you get fully coins.