Steem is a very innovative blockchain-based social media platform where anyone can earn Steem dollars by posting relevant content, curating quality content by upvoting and by holding Steem based currencies in a vest fund, which generates interest.
Interestingly, there are 3 main currencies in Steemit: Steem, Steem Power (SP) and Steem Backed Dollars (SBD).
Steem is liquid and can be bought in an exchange and converted into Steem dollars or Steem power.
Steem Power is basically Steem that is locked in a vesting fund for 3 months. Users can use Steem power to upvote content and get curating rewards.