I have been working on a personal Ghost blog and this is amazing news for me!! Ghost is a joy to use. I am curious about the performance requirements, how it will work with self hosted, I have mine on a cheap VPS.
Activity Pub is much more flexible, the tradeoff being that it's more complex. ActivityPub is basically a flexible CRUD API specifically designed for social networking, with support for federation.
You could fulfill the purpose of RSS with ActivityPub. But, it doesn't supercede RSS/atom, because the simplicity is valuable for the cases those protocols handle.
@hedge Wow, this is big. Fedi needs more macroblogging options to compensate for the domination of Mastodon and other microblogging platforms. And also it being another corporate actor like Meta, but smaller, will create the incentive for Meta to play more fairly in the long run and not EEE the Fediverse with Threads, just like it did with XMPP by integrating it under Facebook almost a decade ago. This is exactly what we need to become and stay mainstream.