Meta adopting ActivityPub has the potential to fast-forward the progress of the social web by years.
Yes, but ...
Unfortunately, it’s likely that Threads will implement only the parts of ActivityPub that serve Meta’s business, ignoring features such as account migration that would allow users to move their followers from Threads to Mastodon or Micro.blog.
It is tempting to see faster progress in general, but do we want progress under Meta's terms specifically?
I don’t worry about Meta embracing ActivityPub and then extinguishing the fediverse as we know it.
I do. Shiny features could create a dilemma for users to either enjoy freedom in the then underdeveloped parts of the fediverse, or to accept a subordinate role to Meta.