It's not Facebook, but it's not decentralized either.
The cyrptocurrency Steem is decentralized, like other blockchain-based currencies. However, this website, Steemit, is not.
A quick DNS lookup (https://whois.icann.org/en/lookup?name=steemit.com) shows that www.steemit.com is using AWS for its DNS services, so it's likely this whole thing runs on someones AWS account.
That someone can shut the site down, censor, or do whatever they want to the content on their servers anytime they want. Furthermore, they can be forced to do it by any government anytime that government wants to. Want an IP address of a user? Want a hash of their password? Want the actual password (by serving up a login page when their IP address is the client that doesn't hash the password but saves in it in cleartext for the FBI)? Government can make them do that.
