According to Bit Degree, Steem coin is a cryptocurrency of Steemit – a blockchain-based social media platform founded in 2014. By Wikipedia's explanation, Steemit is a blockchain-based blogging and social media website that rewards its users with STEEM coins for publishing and curating content.
The Chief Executive Officer of STEEM is Dan Larimer, and he's also the CEO of Bitshares.The pros of using STEEM is: it's a social blockchain that grows communities and makes immediate revenue streams possible for its users. It does this by rewarding them for sharing content. STEEM is currently the only blockchain that powers real applications via social applications like Steemit.