Mark Zuckerberg has announced that Threads is now testing integration with the fediverse, thanks to support for the ActivityPub protocol. In this current integration of the integration, Zuckerberg says this means posts Threads accounts will now be available on Mastodon, Pixelfed, and other services that use ActivityPub.
π Threads starts testing ActivityPub support for integration with Mastodon and more - 9to5Mac