1 ETH = 65,000 SMU. You receive 100 SMU for each referral (~$0.80) up to 5,000 SMU (~$40). Compared to a total supply not that much as it is for the most ICOs currently. But the tasks are done pretty easily. The fact that you only get tokens if you refer other people is of course a huge downside for the most of you and the reason this airdrop only receives 3 stars.