Presumably free Amazon giftcards for filling out the survey and recommending friends.

Upon completing the Universum Career test and registering your email, you received a unique, sharable link connected to your profile. Every time someone participates via your unique link, and this person registers his or her email, that person will be counted as your Referral. The more referrals you have - the more bonuses you can claim and the higher are your chances of winning the Grand Prizes.

The survey takes about 5 minutes. Valid until March 22nd 2015 23:59.

The rewards are:

$20 for 5 referrals;
$60 for 15 referrals;
$120 for 30 referrals;

$500 travel voucher for 100 referrals;
$200 dollar gift card for top 4-10 referrers;
iPad mini 2 for top 2-3 referrers;
$1250 travel voucher for top referrer;

I don't have confirmation for now, because I not yet fulfilled the requirements - however you can find some assurance on reddit.

Referral link
Non-referral link