Major addition to Filtering: Message-Blocking
What used to be just Private Message (PM) blocking now applies to public messages, with a twist.
If you go to a person's profile, you'll see a link there for blocking messages to you from them. If you hit that link, or hit the "Block Messages" link when reading a private message from them, they will no longer be able to send you messages, privately or publicly.
The twist is that if you do this, you also can't write to them.