I think people have been confused for a long time about what the Cool URIs essay means by "change".
This is a particular resource:
http://example.com/latest/
It has representations that change over time, because the conceptual resource "the latest thing at example.com" itself changes over time. This is perfectly fine: the resource that the URI refers to stays the same, but that resource's state is mutable, and the changes in this state are reflected by changes in the resource's representation (what you get by retrieving it.)
This is another resource:
http://example.com/2012/01/02/news/
This representation at this resource probably shouldn't change very much; not nearly as much as the one at /latest/. It's still allowed to be mutable, though! If there's a typo, or a retraction, you're allowed to reach back through time and fix that resource, to make it "the way it should have been" at that date.
A webmaster's responsibility is to make sure his URLs continue to refer to the same things they originally referred to. Conceptually, if you only want to store "the latest news", then you should only have a /latest/, and not a /2012/01/02/news/. Creating the latter is creating a promise that it will stick around, continuing to refer to "the news at 2012-01-02"--a permalink, in the real sense.
I think another important aspect of this is that the (relatively unchanging) resource at /2012/01/02/news/ shouldn't be moved to /archive/2012/01/02/news/ without at least a redirect.
The point being that if the resource still exists, the old URI would preferably still point to it. If you, as the arbiter of the resource, decide to remove it, of course the URI will break.
This is a particular resource:
It has representations that change over time, because the conceptual resource "the latest thing at example.com" itself changes over time. This is perfectly fine: the resource that the URI refers to stays the same, but that resource's state is mutable, and the changes in this state are reflected by changes in the resource's representation (what you get by retrieving it.)This is another resource:
This representation at this resource probably shouldn't change very much; not nearly as much as the one at /latest/. It's still allowed to be mutable, though! If there's a typo, or a retraction, you're allowed to reach back through time and fix that resource, to make it "the way it should have been" at that date.A webmaster's responsibility is to make sure his URLs continue to refer to the same things they originally referred to. Conceptually, if you only want to store "the latest news", then you should only have a /latest/, and not a /2012/01/02/news/. Creating the latter is creating a promise that it will stick around, continuing to refer to "the news at 2012-01-02"--a permalink, in the real sense.