Steem ( STEEM )
Steem.it is a blockchain-based social media platform where users can earn rewards by posting relevant content, curating quality content by up-voting and by holding Steem based currencies in a vest fund, which generates interest.
There are three 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.
When a user up-votes content his steem power gets depleted and then slowly regenerated. Steem Power holders receive interest from their holdings. The more Steem Power a voter has the more revenue he’ll generate for himself (in form of SP) and for the content creator (In SBD).
Steem is a proof of work currency with a scheduled blocktime of 3 seconds. Steem PoW mining is done in rounds of 63 seconds by 21 miners (witnesses). 19 of the miners are pre voted, one is the other with the most computational power, and the last one is selected from a queue of witnesses that did not get on the top 19 voted witnesses.