Clarification about dc:date on a feed?

["Bill Kearney" <wkearney99@hotmail.com>]

Hi all,

Can folks chime in with opinion as to what's supposed to be used in the dc:date
element?

The specs for RSS-0.91 are ambiguous about using pubDate and lastBuildDate.  I'd
like to get a clarification as to how dates are to be indicated in an RSS-1.0
feed.

I can see several issues.  One is the timestamp of when the XML was truly
generated.  Some are statically generated so this timestamp could be considered
some way to check whether a local copy is any 'different' than the one online.
However, a great many feeds are dynamically generated making this timestamp
completely unsuitable for use as a checking indicator.  I'm not unaware of
e-tags and content-header stuff, let's focus on in-feed timestamping for now.  I
recognize protocol negotiation is an important tool it's just outside the scope
of what I'm clarifying here.

Another issue concerns when the content of the items has changed.  A timestamp
indicating when the most recent item within a feed has changed would be quite
helpful for more environments.  This raises the question of whether the
timestamp of content change is item-related or whether something about the
channel as a whole has been altered.  I'd suggest that most folks only really
care about a content timestamp change but the header question does deserve some
consideration.  That way they could tell if the header-related material for the
channel has also changed.

Additionally, how about discussing a dc:date inside the items themselves?  Most
environments DO have the ability to extract this information and a great many
users would take advantage of it.  Can we speak about it?  The module for
aggregation does support it.

The recent dc_terms module also suggests created and modified date, but the
examples only suggest it's use in the header.

I'd like to get a consensus going on making more effective use of dates inside
the channel header and inside items themselves.

-Bill Kearney