sorry but copyright take downs will be one way to take down stuff, steemit inc has had to take down just like one page of stuff its a short list maybe a few dozen posts and their all bollywood movie links and reposted pictures stolen from some photographer who sued steemit inc pissed that someone else was getting paid off their work'
But yeah the blockchin wioll always hold the info so u can just make ur own front end
now the witnesses CAN refuse to deal with certain info but you can ALWAYS do this on Golos hahaha or make a steem fork that is all about hosting sketchy darknet market stuff :D