You are rewarded for having Steem Power. At the moment the reward is around 0.9% per day. This falls each day over the next 12-15months, until it hits 0.18% per day, and then it stay there for the rest of time...
Technical Explanation: https://steemit.com/steemit/@hisnameisolllie/steem-dilution-rate-explained-currently-much-higher-than-you-might-think