Steem has several types of tokens, Steem, Steem Dollars (SBD), and Steem Power (a denomination of VESTS). STEEM and Steem Dollars are liquid while Steem Power is not.
When you are paid on the website Steemit, you can choose to be paid 50% in STEEM Power and 50% in STEEM Dollars, or 100% in Steem Power. Here's an example of a 50/50 payout: If you earn $200 on a post, you will get $100 STEEM Dollars, and 50 STEEM Power*
* this assumes STEEM Power is valed at $2 eachLearn More