Steemit is a different kind of social network. Steemit is NOT an alternative to Facebook.
There are no private things on Steemit and on the Steem blockchain. Except for your passwords (private keys), of course. The Steem blockchain is completely transparent. Everything (except for your passwords) is visible on the blockchain. Post/comment edit history, cryptocurrency transfers and even the amount of money you have in your Steem wallet is publicly visible.
The truth is that "You are totally exposed on the steem blockchain". The only thing no one sees on the blockchain are your passwords which are easily leaked because sometimes people mistakenly send as memo.
On facebook, only part of your information is out there with your permission and terms and guidelines you agreed to.
One problem with the crypto world is that people are using all means to push "so-called" adoption even if it means lying and painting decentralization black and blue with allegations they are more guilty of.
To answer your question, you are more exposed on steem. The only twist there is that on steem , you can keep your real name while on facebook, you are somewhat required to do so, although, i really don't think it is compulsory.
Also, facebook is not safe, sometimes, they go over the board to use your data in ways you weren't aware of.
Priva...what? I don‘t think so. Everything is on the blockchain. There is no real privacy on Steemit.
The block chain is not a palce for privacy other than your account keys. Everything else is 100% visable and trackable. So I think privacy issues are a totally different animal on the block chain compared to normal social network websites.
I signed up to have my Facebook account deleted before all the scandals hitting. I hope they actually deleted my information. But when we where young Facebook was all the craze and all the cool kids had Fakebook.