Adam Mosseri:
Second, threads posted by me and a few members of the Threads team will be available on other fediverse platforms like Mastodon starting this week. This test is a small but meaningful step towards making Threads interoperable with other apps using ActivityPub — we’re committed to doing this so that people can find community and engage with the content most relevant to them, no matter what app they use.
Being in control of who sees my post. Lemmy still lacks more granular post visibility like Mastodon does. If I restrict a message to followers on Mastodon, I know just they would see it, and so would their current instances which are much smaller and fragmented. Compared that to any social media where that’s going to easily be tracked on both sides. Federating with threads doesn’t change this. Also as you said, lack of analytics is nice. Privacy could definitely be improved though. Mastodon direct messaging is still weird and really should use e2ee.