Hello guys, I'm pretty new to Steem.
I read a lot about Steemit, and I have a few questions on Steem blockchain.
Please correct me if I'm wrong.
So Steem is a POS coin that powered by witnesses (is that just another name for nodes?). They are verifying transactions (like on the BTC blockchain) but they also have to store all the content (accounts and posts) right? Do they need to operate hard drives like with Siacoin?
Also is all the content on Steemit stored on the Steem blockchain ? accounts, posts, comments, votes, muted accounts (I saw that you can't see on Steemit.com which users muted you but you can still see it by yourself on the blockchain right?), website url... And is it possible to delete that content or once something has been posted, i'll stay on the blockchain forever ? I mean, it can cause several problems, serious problems. What happens if someone publishes illegal content? It can be copyrighted content, like movies or music, or even worse : pedo, terrorist propaganda (lel).... I know that only text can be uploaded on Steem, pictures and videos have to be uploaded on third-party websites. But still, it's forbidden to distribute access to illegal content even if photos and videos are not uploaded on the site in question. And a .com public domain such as steemit.com can be easily seized.

Thank you in advance for enlightening me (btw maybe everything I said is retarded and I didn't understand anything at all but I had to ask you about that, it sounds very important to me lmao)

edit : Finally, I read that you can upload pictures directly on Steemit