Create an aggregation site which aggregates RSS feeds and outputs them in river of news style pages with the most recent news items first.
Google's online feed reader now allows you to track changes on any page - even those that don't feature an RSS feed. Google will create its own custom feeds for these sites and update the feed whenever it notices a change. Google Reader will display a short snippet of the page changes in the RSS feed.
A simple, open, server-to-server web-hook-based pubsub (publish/subscribe) protocol as an extension to Atom. Parties (servers) speaking the PubSubHubbub protocol can get near-instant notifications (via webhook callbacks) when a topic (Atom URL) they're interested in is updated.