The witnesses are the people and machines that keep the blockchain running. Every three seconds a new block is added to the blockchain and there is no such thing as mining steem anymore so witnesses are the ones that do it. They get rewards and in turn are supposed to give back to the community as @followbtcnews is trying to do. The witness nodes do everything from process blocks to setting the rules of the blockchain so which ones you vote for is very important.
You are viewing a single comment's thread from: