What are the best sites where you can join for new & hot airdrops? 
To me, the best sites where you can join and get good updates about airdrops are; http://cryptocreed.com/airdrop/
https://airdrops.io/
https://airdropking.io/
https://airdropalert.com/
https://airdrops.live/
https://airdropalarm.com/