Clicking on it prevents a post from appearing in a thread when viewed on the web version of the server hosting my account. Eg;
A reply to my post uses an offensive term in the heat of the moment. I don't want to feed the trolls by replying, but I don't want people thinking I endorse that kind of hateful language. So I click Mute Post, and and anyone who views my account on Mastodon.nzoss.nz won't see it.
