The fact, we just get little amount of tokens if we dont have many referral. Mostly the airdrop force us to find referrals as many as we can. Especially who want to invest in their ICO. That's the hard point to do, persuade people to invest there which mostly didn't have good roadmap or whitepaper. The best way that we can do is join the airdrop which also have bounty campaign on it. So we can get extra token by joining both of them. And not waste our time.