Why do the URLs of posts here change?

[Chris Angelico]

On Sat, Jan 10, 2015 at 2:21 PM, Gregory Ewing
<greg.ewing at canterbury.ac.nz> wrote:
> Skip Montanaro wrote:
>>
>> The way this is done, is
>> that the message is removed from the underlying mbox file, and the
>> archive regenerated. That changes the counter for every message after
>> that point
>
>
> Would it help to replace the message with a stub
> instead of deleting it altogether?

I had the same thought, but apparently not, according to the page
Peter Otten linked to:

http://wiki.list.org/display/DEV/Stable+URLs

ChrisA