I don't know if Airdrop is really profitable. May be this thread will help me to understand it more. Though I don't believe much in free stuff.
Its not free man. I look it this way. Most projects expect you to share their project via twitter fb, etc... So you are doing marketing for them and in return, they reward you with a small portion of tokens/coins. For now, I am satisfied, but rly need to w8 for two or three months and see if this was worth it and do coins increase in value.