Steem contrary to Bitcoin, do not require expensive mining rigs which only professional miners can afford, to generate new blocks with latest transactions. It could be said, that Bitcoin uses mining to determine who will generate a new block, effectively by a contest "who will waste more electric power".
Steem in the other hand, use more productive approach and allows users to chose block producers (a.k.a. witnesses) by allowing users to vote for those which brings the most value the network for example by creating interesting projects, promoting Steem, etc.