In reply to:
I don’t want to reinvent PuSH but I do kind of want there to be a way to subscribe one indieweb site to another, and receive a simple ping when there’s an update… (without creating a massive DDOS vector of course)
 
I was thinking of adding PuSH support, is there a reason more people don't use it?
 
@notenoughneon @kylewm I think because not many people are building readers right now. There isn't a lot of need for PuSH until you're consuming feeds! Superfeedr has a pretty simple walkthrough of setting it up: http://pubsubhubbub.superfeedr.com/