This is me trying to understand it:
Instead of services that read your feeds (e.g. Google Reader) having to ASK for your feed periodically, now they can instead just wait until YOUR SITE notifies THEM. Basically a "push" service.
It seems to me this is half the equation. The other half is building services that accept these push notifications. I'm not sure who is already doing that, but I wouldn't be surprised if Google is on it, since it seems like a more efficient way of doing things on both sides (less server resources on both sides).
Two concerns I can think of:
- Is this just as reliable as the "old" way? People not getting feed updates because of a hiccup in the chain sucks for everyone.
- This makes "accidentally" hitting that publish button potentially even more embarrassing than it already can be. Like when you accidentally publish a post instead of a page.
Also check the overview slideshow here.