There's a debate in comments about a Dave Winer 'rant' on a contest to rename RSS. This nugget was in the comments:

Saying that the only way to get content is to have aggregators pulling it is missing a whole other way of doing it, that's proven itself as scalable and resilient over the years: NNTP

I'm not talking about using NNTP directly but taking ideas from it. Having a network of servers that talk to each other, where items propagate between servers, and where users talk to a single server that's close to them instead of reaching all over the world to poll, makes a lot more sense.

Rather than having a million aggregators hitting 20 or 30 sites an hour each, those million aggregators would talk to server, and the servers would talk to each other, so that your aggregator client would simply talk to an “RSS Server” near you to pick up all the things you subscribed to.

No polling involved – at least, not polling of the sites themselves.

If email was implemented the way RSS is implemented, then my mail client would be polling all my friends every half hour to see if they've sent me an email. Nobody would implement email that way – but that's what RSS is.

SMTP moves mail from the author to a server close to the user, in the background, maybe involving multiple servers in between. Long term, I think this is going to have to happen with RSS as well.
Steve Tibbett [apple] 12/9/03; 5:07:54 PM

My favorite part is the sentence about email working like RSS. Classic.