It'll be interesting to see how much of ActivityPub Facebook supports in their product.
When Google Reader came out for RSS their trick was to break RSS by not supporting a key feature.
This did huge damage that we're still dealing with long after Google is gone.
now here's some good news.
there's no guarantee they'll be successful on terms that matter to them.
unless a half billion people use their service, it's probably not worth continuing, for a company the size of facebook.
podcasting has withstood countless attacks like this, and has always been left standing as unsullied as ever.
but podcasting is "really simple" and the benefit of federation is well known TO USERS. That's been what's kept it from being pwned by bigco's all these years.