Invite friend, family, colleagues, other people and get reward from their future earnings. I believe this gives strong incentive to most people here to go out and do referrals because you know you will be rewarded once people you invited joins and start posting, commenting. People joining through your invites also get your support on their content if you follow and vote their content.
I understand this way of rewarding referrals, but be careful not to get into a pyramid game here. I would think: 1-time reward for a successful referral instead of a percentage for all what the referred user is earning in the future.