Any site could publish a syndication feed using one of a couple of standards (RSS 2.0 and Atom ultimately dominating), and users could choose to subscribe to any feed in newsreading software. The most popular OS X app was NetNewsReader, which remains under development.
Newsreaders used pull instead of push. The feed formats were in plain text, fed by web servers like any other page. At regular intervals, a newsreader would poll every syndicated feed's web server to ask if it had changed in that time. If so, it would bring down a new copy of the file. The site never knew anything about you beyond an IP address and newsreader version. (Some feeds required a user name and password, but that was never very sustainable as a way to prevent access.)
If you had hundreds of feeds, your newsreader might make tens of thousands of requests per day. Multiply that by millions of people using newsreaders.
This was unwieldy, and aggregation and synchronization services rose to allow a central point where a server would request updates once and then distribute to every synced account that subscribed to that feed. These services also allowed you to have every newsreader you used on every device, including mobile, stay up to date both in terms of which subscriptions you maintained and which you'd already marked as read, as in email.
Then Google entered the scene with its Reader web app in 2005, which also had sync services, and killed almost all competition. When Google pulled the plug on Reader in 2013, there was no obvious replacement, though some have risen since.
Social networks appeared for some to render RSS pointless. A stream of always timely links from other people — and brands and other advertisers — replaced some, but not all of its utility.
All three promise rich media, beautiful layouts, seamlessly integrated advertising (why is that a good thing for readers?), and curation from major media brands. All are free. All are designed to "enhance engagement": to divert precious attention from elsewhere to these particular apps, and by grabbing high-quality attention, sell high-value ads.
News that you can use or abuse
The reason for my initial excitement at News is that I misunderstood what Apple's VP of Product Marketing Susan Prescott was showing. I thought News was going to be a rebuttal to Google's disinterest in Reader, a product that was exceedingly popular but they couldn't figure out what to do with.
I thought News would combine pull and push. On the one hand, readers would add sites they were interested in, and Apple would scrape pages or rely on RSS to produce something like its Reading List stripped-down text view in Safari, only better. On the other, Apple would push the availability of both partner sites that had formatted using its richer Apple News Format (not yet released) and those it had opted to include via RSS or which sites had specifically submitted for inclusion.
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