You are right, from a technical perspective RSS is pull technology in that the publisher (in most cases) does not notify the aggregator when a new entry is published, so the aggregator has to poll on a regular basis.
But from an aggregator user perspective polling looks like a form of delayed push.
There has been floated several ideas on how to turn RSS into a true push technology, which would greatly enhance the value of aggregators, imo. There is the concept of clouds:
Or to look at what Lucas was saying in a slightly different manner, the aggregator pulls in the feeds and then pushes them back at the user. Automated pull really, but it feels like push. And unlike Lucas I'm not really sure why you would want anything more push then that, e-mail is close enough to its limit, do we really want any more push in our lives?
It's Pointcast all over again. A lot of the Pointcast channels were news aggregators disguised as news outlets (though that's certainly the mainstream of newspapers today too). And the Pointcast client polled. Now all we need is the free, ad-supported RSS browser, and we're there.
I have to disagree with Kevin and Abe. RSS aggregators are designed to simulate push. Unlike Pointcast, RSS is a bottoms-up, grassroots technology, so when a feature is implemented it is usually because people want it. That means we have to ask ourselves why users care about timely updates for RSS and they didn't care for it with Pointcast. I think the reason is that Pointcast pushed generic, official news sources that could be found on any website with an AP feed, and did not support interaction via comments. Go to Slashdot and you will see how important it is for people to post comments right away, as threads tend to form from the initial posts.
Interactive technology is enhanced with real-time behavior (look at the popularity of IM), Pointcast was not interactive, RSS is. If you think email is all that is needed for push, well, if you wanted to write an email-based aggregator you'd have to poll.
Just because push got a bad rap 8 years ago doesn't mean publish/subscribe is not an essential part of advanced content distribution systems. Polling is a hack, any programmer worth his salt will admit this.
5. Jens Alfke on January 6, 2004 12:24 AM writes...
What Lucas said. And email itself is only push-based till the "last mile": SMTP is a true push technology, but both POP and IMAP require the client to poll.
This is definitely a problem with RSS. People who provide feeds continue to grip about "broken" newsreaders hammering their sites too often, even if the newsreaders are being nice about using If-Modified-Since headers. A really-truly-push equivalent of RSS would be a great advance.
Forgive me if I'm going astray, but I read Ross's question a bit differently. For me, it's not about the current way that RSS is distributed, which today clearly is pull (scheduled polling), though it may at some point become true pub/sub oriented, when everyone gets around to developing that great big bus in the sky.
No, Ross's question is about permission and attention. About the relationship between reader and writer. RSS requires the reader (or, more generically, "feed consumer") to make an active choice to engage with the writer ("feed producer"). Sure, my aggregator may poll once every 60 minutes, and to me, in my daily work flow, that might feel like "push." But my RSS subscription list is managed reasonably closely...reflecting the nature of /choice/ that I have in subscribing to those feeds. The reader chooses to pull content that the publisher's pushing.
Man, comment spam can be like saying Hitler to kill a good discussion.
So obviously I believe its Pull. Both technically and socially. Michael makes a great point that its about choice, the ability for readers to drive their own consumption. You determine what to sub/unsub, in some cases by what format (RSSvX, Atom), when to poll. If you are using an aggregator that only polls by schedule, you miss the satisfaction of getting the latest when you want it (of course, using NetNewsWire means a repeated hand cramps from R+Shift+Function).
User choice and control enables self-organization that differs from the nicely packaged service that Pointcast represented. Yet for all this Pull, publishers know so very little about whats being demanded. What's interesting is when polls are pooled, more is made transparent and perhaps even self-organizing.
Hehe... such is life... On the other hand, the fact that you get spam is closely related to the fact that anyone can pretend to be anyone... Just look at how your comment form is setup... certainly there must be a better way to handle identification...
"User choice and control"
Yes, this is key: a user needs to explicitly "opt-in" (e.g. subscribe) to a feed. This is a good thing :)
1. Lucas on January 5, 2004 8:37 PM writes...
You are right, from a technical perspective RSS is pull technology in that the publisher (in most cases) does not notify the aggregator when a new entry is published, so the aggregator has to poll on a regular basis.
But from an aggregator user perspective polling looks like a form of delayed push.
There has been floated several ideas on how to turn RSS into a true push technology, which would greatly enhance the value of aggregators, imo. There is the concept of clouds:
http://blo.gs/cloud.php
And ATOM folk have alluded to the possiblity that it will support push, but it doesn't seem to be a priority, which is a shame...
Permalink to Comment2. Abe on January 5, 2004 9:25 PM writes...
Or to look at what Lucas was saying in a slightly different manner, the aggregator pulls in the feeds and then pushes them back at the user. Automated pull really, but it feels like push. And unlike Lucas I'm not really sure why you would want anything more push then that, e-mail is close enough to its limit, do we really want any more push in our lives?
Permalink to Comment3. Kevin Schofield on January 5, 2004 10:15 PM writes...
It's Pointcast all over again. A lot of the Pointcast channels were news aggregators disguised as news outlets (though that's certainly the mainstream of newspapers today too). And the Pointcast client polled. Now all we need is the free, ad-supported RSS browser, and we're there.
Permalink to Comment4. Lucas on January 5, 2004 10:40 PM writes...
I have to disagree with Kevin and Abe. RSS aggregators are designed to simulate push. Unlike Pointcast, RSS is a bottoms-up, grassroots technology, so when a feature is implemented it is usually because people want it. That means we have to ask ourselves why users care about timely updates for RSS and they didn't care for it with Pointcast. I think the reason is that Pointcast pushed generic, official news sources that could be found on any website with an AP feed, and did not support interaction via comments. Go to Slashdot and you will see how important it is for people to post comments right away, as threads tend to form from the initial posts.
Interactive technology is enhanced with real-time behavior (look at the popularity of IM), Pointcast was not interactive, RSS is. If you think email is all that is needed for push, well, if you wanted to write an email-based aggregator you'd have to poll.
Just because push got a bad rap 8 years ago doesn't mean publish/subscribe is not an essential part of advanced content distribution systems. Polling is a hack, any programmer worth his salt will admit this.
Permalink to Comment5. Jens Alfke on January 6, 2004 12:24 AM writes...
What Lucas said. And email itself is only push-based till the "last mile": SMTP is a true push technology, but both POP and IMAP require the client to poll.
This is definitely a problem with RSS. People who provide feeds continue to grip about "broken" newsreaders hammering their sites too often, even if the newsreaders are being nice about using If-Modified-Since headers. A really-truly-push equivalent of RSS would be a great advance.
Permalink to Comment6. michael sippey on January 6, 2004 2:22 AM writes...
Forgive me if I'm going astray, but I read Ross's question a bit differently. For me, it's not about the current way that RSS is distributed, which today clearly is pull (scheduled polling), though it may at some point become true pub/sub oriented, when everyone gets around to developing that great big bus in the sky.
No, Ross's question is about permission and attention. About the relationship between reader and writer. RSS requires the reader (or, more generically, "feed consumer") to make an active choice to engage with the writer ("feed producer"). Sure, my aggregator may poll once every 60 minutes, and to me, in my daily work flow, that might feel like "push." But my RSS subscription list is managed reasonably closely...reflecting the nature of /choice/ that I have in subscribing to those feeds. The reader chooses to pull content that the publisher's pushing.
Or something like that.
Permalink to Comment7. Zap on January 6, 2004 5:55 AM writes...
Yes, RSS is a pull technology... what's wrong with that? The entire Web is pull after all...
But, as mentioned previously, there are obviously better way to know about a RSS update than polling every half minute.
RSS 2.0 provides the notion of a "rssCloud", which allow to subscribe to a RSS feed for change notifications.
Rohit Khare's mod-pubsub enables publish and subscribe messaging over HTTP.
One could imagine (ab)using Jabber or such for change notification.
And so on...
So... the issue is really with the rustic state of today's news aggregators, not with any intransic deficiency in RSS per se.
Permalink to Comment8. Liudvikas Bukys on January 6, 2004 11:23 AM writes...
pull + poll ~= push
Permalink to Comment9. Kreditkarten on January 6, 2004 11:38 AM writes...
Cool Blog! Ralf
Permalink to Comment10. Ross Mayfield on January 7, 2004 4:29 AM writes...
Man, comment spam can be like saying Hitler to kill a good discussion.
So obviously I believe its Pull. Both technically and socially. Michael makes a great point that its about choice, the ability for readers to drive their own consumption. You determine what to sub/unsub, in some cases by what format (RSSvX, Atom), when to poll. If you are using an aggregator that only polls by schedule, you miss the satisfaction of getting the latest when you want it (of course, using NetNewsWire means a repeated hand cramps from R+Shift+Function).
User choice and control enables self-organization that differs from the nicely packaged service that Pointcast represented. Yet for all this Pull, publishers know so very little about whats being demanded. What's interesting is when polls are pooled, more is made transparent and perhaps even self-organizing.
Permalink to Comment11. Zap on January 7, 2004 6:00 AM writes...
"Spam"
Hehe... such is life... On the other hand, the fact that you get spam is closely related to the fact that anyone can pretend to be anyone... Just look at how your comment form is setup... certainly there must be a better way to handle identification...
"User choice and control"
Yes, this is key: a user needs to explicitly "opt-in" (e.g. subscribe) to a feed. This is a good thing :)
"polls are pooled"
Hmmm...?!? Care to elaborate? :)
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