Sunday, May 22, 2005, 3:35:16 AM, Tim Bray wrote:
> I'll repeat that. The only difference is that there might be changes > not considered significant by the publisher. > So the only reason why atom:modified can ever be more useful is if > you disagree with the publisher's opinion as to what is significant. > If you disagree to this extent, what reason is there to believe that > you will agree with the publisher as to what constitutes a change? > Or that you will trust the publisher to actually insert a changed > version in the feed upon a change that is not considered > significant? Or that you will trust the publisher not to just lie? > And if you don't trust the publisher on these things, then why would > you believe atom:modified anyhow? > I just don't believe that the difference between updated and > published is operationally useful in the slightest. > In future argument, please don't argue any more that it's important > to maintain successive versions or to track temporal differences. I > believe all that. Instead, please explain why you expect to disagree > with publishers' opinions as to what is significant and, in the case > where you disagree, you feel you would trust atom:modified. > Absent such explanation, I am totally -1 on atom:modified. -Tim Let's assume first, that you aren't deliberately putting false data in your own feed: When you post an entry to a feed it is a subjective decision whether you change the atom:updated element based on your opinion of whether the change is significant. If I want to keep an archive of your feed, then I trust that atom:updated 100% reflects your opinion on significance. But it doesn't mean that I share that opinion. I may have a more discerning criteria, so I want to represent a copy of all instances. It isn't a question of trust, in this case I trust that you have used a truthful value of atom:updated. A modified date is not subjective. When you post an entry to a feed, this communicates to the subscriber the modified date, nothing more. An archiver can use this to preserve the temporal ordering of entry instances. (Perhaps a better use case, would be to replace "I" in that explanation with "The archiving feature of your posting software or provider") On the other hand, if you are deliberately putting false data in your own feed, Atom does not attempt to deal with this situation, whether atom:modified is included or not. -- Dave
