Re: Intent to revive "expires" header from draft-ietf-mailext-new-fields-15

On Tue, 2008-07-29 at 15:58 -0400, Hector Santos wrote:
> Michael Welzl wrote:
> 
> > I don't understand that. I have seen wide agreement that we
> > don't want to specify behavior #1, so why do you call this
> > more realistic?
> 
> Because the practice of automatic purging already exist without any 
> flags, and clearly without user permission.  That is reality.
> 
> This proposal attempts to introduce a new header that would require a 
> change and alteration ($$$) of this existing design and practice.
> 
> IMO, this is asking much more than what is realistically more 
> possible, which is to simply state:
> 
>     Servers which employ automatic purging of old messages
>     MAY let this field influence the purging process.
> 
> Once there is a criteria of user permission, I think you can run into 
> an ugly game of users having a false illusion of controls they never 
> had in the first place.

I disagree. Prescribing and suggesting things is what RFCs should do;
this is like drawing an architectural figure.

In reality, people may or may not follow the specs, and you
can always have systems which misuse things that you prescribe -
this is like the house that is then built based on the figure.

Now saying that servers MAY let this field influence the
purging process (although we don't want them to, unless
given explicit permission by the user) is like saying that
the side wall of the kitchen may or may not end up being
totally straight at the corner of an architectural sketch,
just because this is how people build things sometimes.

Cheers,
Michael