On Sun, Jan 11, 2009 at 8:50 PM, Martin Atkins <[email protected]> wrote: > > > The work on using Atom to encode activity streams has raised what seems to > be a more general issue with Atom that I thought I'd bring up over here to > see what insight this group can bring. > > In the "normal" case of a feed of entries a user has published, "published" > quiet sensibly represents both the time the entry was published and the time > it appeared in the feed, by definition. > > However, when the feed is of something else, these two times are no longer > necessarily the same. > > Consider for example the feed that YouTube publishes of a user's "Favorite > Videos". In this feed, the entry-level atom:published tells us when the > entry was added as a favorite, *not* when the entry (i.e. the video) was > posted to YouTube by its author. > > However, Digg's equivalent "Favorite Articles" feed (which is actually RSS > 2.0, but let's pretend it's Atom for the sake of this discussion) has the > published time set to the time the article was originally submitted to Digg, > *not* when it was added as a favorite.
I might be thinking too much as a library geek, but it seems to me that the YouTube approach is more correct. The activity stream work is raising good questions and I'd say you need a clear idea of the abstract model of an activity and its consituent entities and actors. This sort of thing can get pretty hairy (Google "FRBR" or CIDOC-CRM" for real fun) if there is not a pretty good shared understanding of what's what. Unless I am mistaken, an activity stream is making assertions about activities and to mix in metadata about the underlying things (like when a video was originally posted) seems off. Of course, a linked-to Atom entry representing that media item (specifically it's YouTube instance) probably would have the that information. FWIW, I am hoping this Activities stream will (like Atom itself) have all kinds of applicability outside the social networking context in which it is being created, so I hope the modeling is very solid. To me, a set of activity streams seems to offer lots more opportunity for semantic mining than "linked data in RDF" since the human actors are so much more visible. (Which is why I find the act of making it a favorite more pertinent than when it was posted, which I can find by other means). > > My question, then, is which of these approaches is correct. The Atom > specification is (intentionally?) very vague about what this time > represents, but it does refer to "the entry". It's open to interpretation > whether "the entry" means "the actual atom:entry element in this feed" or > "the item that this atom:entry element describes". > > Do you think it would be vaulable to have an optional extra element that > indicates when the entry appeared in the current feed/collection? (This > would effectively make YouTube wrong and Digg right.) > > (I'm told that Digg couldn't actually implement this element even if it was > specified, because they don't retain a timestamp on their "favorite" > relationships, but at least it would reduce the ambiguity about what That's a significant omission on Digg's part, I think. --peter keane > atom:published represents.) > >
