Steem blockchain is the blockchain made for all people who can do trnacation without any fees. Steem coins are made from this blockchain and steem dollars which run on the ERC20 tokens.
Steem blockchain has several others platfron like musing, steemd, steemit, etc which are running smoothly on steem blockchain.
Steem blockchain has many other fubction which we can read their roadmap in their official site of steem.com where they have completely said about theid platform and how they work.
Steem blockchain never shares your private data to any other platform as this data even steem platform cannot generate it because of their smooth privacy and secured.
Our data and our wallet balance in steemit are totally secure and responsibilities are taken by the steemit team itself.