creation vs availability date in <dc:date>

["kristjanjansen" <kika@sloleht.ee>]

DC guide states:

<i>Typically, Date will be associated with the creation or
availability of the resource.</i>

There are cases when resource creaton and availability dates are 
different. For example - an online magazine articles are originally 
created earlier, but complete online edition rolls out (and RSS will 
be updated) once a week.

What <dc:date> should I add to <item>s, and what to <channel>?
Item creation date to <item>, RSS channel creation date to <channel>?

How aggregators take advantage of <dc:date>? 
When <channel> date and <item> dates are different, who will overload 
who?