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Joshua Allen wrote:
> millions of people use aggregators which use pubDate to
> mean "this article is 'new' if pubDate is > Now()".
Yes. They do that. Unfortunately, they are doing the wrong
thing. It seems that many of the developers of aggregators have
decided that pubDate is an indication of "newness" and such, allows
them to build "neat" date filtering features... However, many RSS feed
generators treat "pubDate" as "created-date." The result of this
mismatch is that many "updated" items are discarded as "old" by news
aggregators.
The RSS generators treat "pubDate" as "created-date" in order
to ensure that a sort-by-pubDate will result in an ordering which
reflects the order in which items were created in the blog. When these
RSS generators "update" or "modify" an item, they will often leave the
"pubDate" unchanged so that the ordering of the blog is not disturbed.
Just the other day, I had a user on the phone that complained
that "PubSub was showing fewer matches than some other site." It
turned out that the user was comparing results filtered through his
news aggregator with results that were displayed on a web aggregator
at the other site. For the particular time period, we had almost
identical results as the other site, however, the news aggregator that
was being used to read our feed was discarding all items "older" than
one day and it was using the "pubDate" to determine "age" of the
items. When we checked the history of these items, we found that even
though many of them were dated many months ago, they had actually been
modified very recently.
Thus, we see that many of the aggregators actually have a
*different* understanding of pubDate then the rss publishers do! Of
course, this looks like "everything is fine" unless you dig under the
covers a bit and discover the impedence mismatch -- or you are the one
that gets emails and phone calls from angry users.
The confusion over the meaning of pubDate is only one of many,
many problems with RSS as we know it today. In order to address user
needs, we either need to "fix" RSS or move to something new. Given
that RSS has been declared "closed" and "never to be amended," we're
stuck moving to Atom -- *In order to provide our customers the service
they demand.*
bob wyman
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