It could be implemented as some type of extension to RSS.

No extension is necessary. There's nothing that says a website has to have exactly 1 or 0 RSS feeds and that they most be for global syndication. Anyone in control of their site can dump a plain ol' RSS (or Atom, or JSON) feed at /foo/part-3-has-been-posted.xml. I've done this on my own site.

This is not (really) a technical problem. It's a cultural one—getting people to actually make hyperspecific micro feeds available.

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akoboldfrying 7 days ago | parent [-]

100% this. Per-topic RSS feeds solves this perfectly.

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waterproof 7 days ago | parent [-]

Nah an RSS feed has the ability to contain n feed items. This proposed new protocol would have a maximum of 1 item. The closed contract (1 notification only, ever) makes sure that it doesn't become yet another avenue for producers to push content that you didn't ask for.

	▲	akoboldfrying 7 days ago \| parent [-]
		"RSS but for just 1 item" and "A brand new protocol that is functionally equivalent to RSS for just 1 item" are both just contracts. What makes you think that the latter is more enforceable?