See also here.
What does Hubzilla have that gives them better tools to fight this?
By default, you only see posts from people you follow, and replies to their posts. And by replies, we mean replies to each particular thread.
Unlike Mastodon, all posts and replies are part of a thread (like a forum post or a Facebook-style social media post). Both the administrator and the person who started the thread can delete comments within that thread.
This also means you can unfollow specific conversations (threads) while continuing following someone’s channel.
With Mastodon, people can randomly mention you and you are notified of the post. With Hubzilla, this is turned off by default, although you can turn it on if you want. Spammers can’t spam you by mentioning you.
And then there are the various ways to block channels.
So spammers can’t get into your inbox very easily, and if they do, they are easy to block.
