Yes. This. This would fix the deluge of duplicates I'm seeing as people start pushing out the same stuff via twenty different services. - James (@willia4)

It's just such a simple concept, presumably with a simple implementation, and it could make everything so much better. Imagine a preference in FriendFeed that was "Don't show duplicate items", and then you only ever see any item once regardless what service it originated from and was pushed to. - Dave Slusher

Dave -- It could also merge discussions for identical items. Which could be amazing. - James (@willia4)

I know from tinkering with the API that all FF entries have GUIDs. But besides FF originated posts, it comes a little too late in the pipeline. - Paul Reynolds

Paul -- Most things have guids (in the sense that they're globally unique identifiers). Every blog post, twitter update, flickr set, etc. has a globally unique URL. i don't think it would be too difficult to start matching based on that. - James (@willia4)

True, and I hadn't considered that. Even within a single service, commenting on a FriendFeed flicker comment could collapse with comments on the Twitter auto-post about it. That would be a huge win. - Dave Slusher

The GUID idea would help, and many providers do have them. However, the GUIDs are useless without everyone conforming to the "original source". For example, a blog post has one GUID but the Google Reader share has a different one. Having GoogleReader or even a share on FriendFeed use the same GUID as the original blog post would be awesome, but in some cases we cannot easily get the source GUID. - Rob Diana

Rob -- Yeah. There's definitely some work there (mostly in the getting all the different services to agree to do the same thing). Though even with Google Reader, the title of the post in Reader is the URL back to the original (or, in some cases, through FeedBurner). So I think it could still be sniffed out in a lot of cases. - James (@willia4)

Mark Pilgrim had some good thoughts on this back when they were working on the intiial Atom spec: http://diveintomark.org/archive... - Ken Kennedy

There are two big issues at play here: The existence of GUIDs and the propagations/preservation of GUIDs. At the very least, all the things consuming RSS/Atom feeds should preserve the GUID from the feed. Google Reader and FriendFeed should not mint new ones for items that come in with existing ones. Step 2 is getting them to use the URI for each item as the GUID. - Dave Slusher

Good luck ... some blogging services can't even seem to get GUID's in RSS feeds - andy brudtkuhl