Will there be restrictions?
SN release: wild west mode 🤠 #72602
tl;dr: You can flag content (posts or comments) for whatever reason. When some threshold of flags versus upvotes occurs, the content becomes "OUTLAWED". The only way you would see content that was OUTLAWED is if you enable "Wild West Mode" in your settings.
Can this "flag" feature be abused? Of course. Has it been abused? Monero shills whose content was not necessarily welcomed by the vast majority of users on SN might say yes, yes the "flag" feature has been abused. A few rage quits have occurred following the introduction of this flag feature. The response by the remaining 99.9% (?) ranges from "Meh" to "Bye, Felicia".

SN release: greeter mode #74511
tl:dr: Posts and comments have a cost of at least 1 sat. Newly created accounts do not have sats, unless the user deposits some themselves. That limits many of them from participating. So new accounts are granted 2 free posts and 5 free comments. But then the problem becomes that without any cost, spammers could (and did) create new accounts to spam, and abuse SN. So now with this change, content from these new accounts is not visible to everyone else, except for those who have modified their settings to be a "greeter". A greeter can upvote content from a new user and that will help the new account to "graduate" (?) so that they are no longer a "new" account and their content will then become visible to all. A spammer would, presumably, not get upvotes and thus their spam content will not visible to all.