> the main point is to separate publishing and distribution, making publishing far more accessible and decentralised. for that to happen, I guess, from a publisher's point of view, the system should be pull based.

Oh, I completely agree with that assertion: Static content hosting is much easier than stateful subscription management, knowing which aggregators to post to etc.

I just think that this does inherently put more work on the subscribers, and there's no real way to do it efficiently in a relatively flat architecture (with subscribers directly polling publishers). WebSub helps with pure distribution, but not with aggregation (e.g. to allow keyword/hashtag search), for example.

That doesn't mean it's not worth still designing a system like that (in my view, the benefits are significant!), but I wouldn't call it a performance win.