anything you can ctrl+v is fine
it's also fine when you're translating text, writing stuff from images etc

don't use it for greentexting as mentioned, cosmetic formatting (there are bullet points or bbcode), putting words to someone's mouth (like false quotes, you see this on 4chan) as well as actions (eg. >doing x instead of y), and some other stuff you wouldn't even know about unless you saw on 4chan (>tfw no gf)

most R8.e bans issues are for greentext stories, don't overthink it