Similar to Mute Post, but a server admin can use it so that a post doesn't appear anywhere on the web pages of that server. Eg;
A reply to my post uses an offensive term in the heat of the moment. We don't want to feed the trolls by replying, but we don't want people thinking our server endorses that kind of hateful language. So the server admin clicks Silence Post, and and anyone who visits Mastodon.nzoss.nz won't see the post anywhere on the website.