Facebook wants to completely dominate everything about Social Media and does not want any other social platforms to succeed. FB either buys competitors or copy them exactly and then destroys them. Look what they are doing to SNAPCHAT. However, I do not think FB can copy Steemit since steemit is decentralized which FB cannot adopt and lose control of their centralized moled where they it has full control on. I think FB will try to imitate Steemit as much as possible . What I am afraid of is that Mark / FB can buy huge amount of Steem token and have tremendous influence by having steem power voting.