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.
The funny part is that blocking the instance makes it more likely that people migrate to threads. We’ve seen that when lemmy instances defederate from the larger problem servers, people will jump ship to be back in those larger communities.