Yes, people on any Fediverse instance (not necessarily Mastodon) will be able to follow users on threads.net and vice-versa. https://www.theverge.com/2023/12/1

Yes, people on any Fediverse instance (not necessarily Mastodon) will be able to follow users on threads.net and vice-versa. https://www.theverge.com/2023/12/13/24000120/threads-meta-activitypub-test-mastodon https://www.theverge.com/2023/12/13/24000120/threads-meta-ac...