So basically one way cross-posting from Threads to the Fediverse... for now, trust us. Kind of like an RSS feed. No ability to comment back from Mastodon, and no ability to post on Threads from Mastodon. If you want to respond to something you see from Threads, you will need to create a Threads account and go there. Seems like a pretty obvious Threads marketing initiative and a play to undermine the Fediverse. Kind of as predicted, this is not "federation".