Paul Buchheit
What’s SUP?: FriendFeed’s Modest RSS Proposal - Webmonkey -
What’s SUP?: FriendFeed’s Modest RSS Proposal - Webmonkey
"Think of it this way: When you go to the movies, you don’t go around to each theater to see which movies are playing and when; it would take all of your time and effort running around from theater to theater. Instead, you check the kiosk out front. Your blog publishing system provides a RSS kiosk, or ping feed, to let FriendFeed (and potential RSS readers) know when and what has been updated since its last visit. Friendfeed doesn’t have to go theater to theater to see which movie is playing. It also checks all RSSs in a domain at once, eliminating the need to download each one separately. Polling is less frequent, but more accurate. By cutting out a lot of wasted data transfer, it reduces the load and gets the relevant information directly." - Paul Buchheit from Bookmarklet
Where can I download the code? - friendfeed
So we need an index for the RSS feeds. Who's gonna post the index of indexes? - Bill Sodeman
I clicked on Paul's link to the code, but it was hard to read because the whitespace was collapsed. Looking at the source it seems that they're nesting the code within tables within <pre> tags. Since <pre> can't contain tables, my browser is ignoring the <pre>s. Why would they do that instead of just putting style="collapse-whitespace:pre" on the table? - Gabe
Are you still using IE3 Gabe? - Paul Buchheit
No, Paul, I have a modern browser: IE 6.0sp2. - Gabe
I don't know if I'd call IE 6 a "modern browser", considering it was initially released over 7 years ago... in any case you can view the source in plain text here: http://simpleupdateprotocol.go... - Simon Willison
I wouldn't call IE6 a modern browser either, but 14% of the traffic to still comes from it, so it does need to be supported -- I'll open a ticket to investigate the issue (I don't have access to Windows right now to confirm). Though @Gabe, since you're a technically inclined person, I'm curious why you are running IE6 rather than FF3 or IE7. - DeWitt Clinton
Most of my clients are still running IE6, so I know that when something works on my machine, it will work on theirs too. Besides, I haven't really found a feature in IE7 or FF that is worth upgrading for. And honestly, I would consider it a bug for a browser to render a block element like a table inside a pre (which only allows certain inline content), particularly on a page that specifies XHTML Strict. I expect the browser to either ignore the pre (like IE6) or ignore the table. - Gabe
Cool, thanks for the feedback Gabe. I opened a ticket here: Please feel free to add more detail to that ticket and star it so you can follow the progress. Cheers! - DeWitt Clinton
Thanks Paul. It's definitely an issue that needs to be dealt with. - Daniel Shaw
Since I can find colliding user IDs easily with MD5, is there any risk of a DoS attack? - Steve Weis
I'm not sure what you're asking Steve. Each site generates their own SUP-IDs, so they would be DOSing themselves. - Paul Buchheit
ok plea to all bloggers- please stop using "modest proposal"- you're referencing Swift who was writing satire, about killing Irish babies to prevent/deal with famine. Almost all blogs with this play on the phrase "modest proposal" are not being satirical... so it's a reference without meaning.. I get confused easily, granted. And, not just this post, but there have been others... OK english major out. Thnx. - anna sauce
anna: Raymond Chen has much better modest proposals ( - Gabe
Paul, maybe I'm misunderstanding the protocol, but I can pick a name that intentionally collides with someone else's SUP-ID. Is there any expectation of collision resistance? - Steve Weis
Steve, each SUP feed has its own SUP-ID space, so you really can't cause problems with other people's feeds. If that's not what you mean, please provide an example of what you have in mind. - Paul Buchheit
@Gabe Raymond's proposal sounds sincere, so it's not really playing off of Swift's joke. Sigh. I guess nobody reads Swift anymore. He was funny! - anna sauce
Steve, IF the service assigns SUP-IDs as md5(username), then yes, you could theoretically get a username that collides with another. But: usernames are usually short, and so you probably won't be able to find a collision with just a few (tens of) characters. Also, as Gary and Paul said, the provider assigns SUP-IDs, and it's in their interest to assign them in a collision-free manner; at the very least, they can hash a secret salt value together with the username. - Tudor Bosman
I've noticed that there is definitely some confusion around SUP. People have said comments like "I'll add it to my blog soon", but I don't think they understand that doing so could actually send MORE traffic to their personal site than they were getting before (from FriendFeed). I think it might help to clarify that this is really useful for large providers like YouTube,, Twitter, etc. Personal WordPress installs won't likely benefit. Please correct me if I'm wrong :) - Patrick Lightbody
Patrick, for personal WordPress installs, it would be better to use a shared SUP feed. I'll probably write one when I get a chance. - Paul Buchheit
SUP is also good for providers that aren't big yet but expect to get big, like OurDoings. - Bruce Lewis from fftogo
Until SUP is widely adopted, one feature I'd like to see is "refresh my feeds" button that instructs the backend to refresh the feeds I own right away. - Misha Dynin