Subject: [Asrg] Sender pays vs the third world

From: Matt Sergeant <[email-masked]>
Date: Wed, 5 Mar 2003 11:52:37 +0000 (GMT)

I'm new on the list so forgive me if this has been mentioned already (the 
archives don't seem complete).

It seems to me that sender pays means the third world gets excluded from 
email communication. Whether it's actual money or if it's just CPU cycles, 
that model simply doesn't work for a group of people trying to communicate 
effectively with "richer" nations. You might as well just use 
http://www.blackholes.us/

That's all I really have to say.

Matt.

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From: "Eric S. Johansson" <[email-masked]>
Date: Wed, 05 Mar 2003 11:53:04 -0500

(re-send with proper return address.  Changing domains is so traumatic))

> http://www.blackholes.us/

not true.  If you design the sender pays system correctly, even weak machines
can participate.  In the camram model, only the first couple of messages have
"high-cost" Stamps.  Every other message to a known recipient or from a known
recipient comes at a much lower cost.

---eric

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From: Kee Hinckley <[email-masked]>
Date: Wed, 5 Mar 2003 11:35:34 -0500

>archives don't seem complete).

No kidding.  I looked at the archives and thought, "Boy, this is low 
volume for a list about spam."  Then I got today's email!

>effectively with "richer" nations. You might as well just use

This is not an obviously solvable problem.  What we love about email 
is that it allows anybody to communicate with anybody on an equal 
basis.  Anyone who argues that we need to move to a sender-pays model 
is going to inherently screw with that beauty.  To strike a balance, 
you need to move the bulk of the cost to bulk senders, and give the 
individuals a free ride.

Spammers will, however, find ways around that.  Even a system in 
which all email is "identified" doesn't prevent people from adopting 
multiple identities.  In addition, spammers may elicit help of 
individuals (willingly or unwillingly).  We've already seen some 
trojan spam software.  And reportedly some "free" porn sites are 
asking their users to periodically type in the text that see in a 
graphic image--an image that they snarfed from the automatic signup 
for a free email account.  (The irony of a computer enlisting the 
help of the distributed computing capabilities of human pattern 
recognition is lovely.)

None of which is to say that we shouldn't use such a model.  Merely 
that we need to figure out what the unintended consequences are, and 
whether the cost of the new model outweighs the cost of the 
consequences.

-- 
Kee Hinckley
http://www.puremessaging.com/        Junk-Free Email Filtering
http://commons.somewhere.com/buzz/   Writings on Technology and Society

I'm not sure which upsets me more: that people are so unwilling to accept
responsibility for their own actions, or that they are so eager to regulate
everyone else's.
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From: Matt Sergeant <[email-masked]>
Date: Wed, 5 Mar 2003 17:53:05 +0000 (GMT)

> recipient comes at a much lower cost.

The latter part does not make my statement false. There are lots of
systems where the majority of email recipients are first-timers.

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From: "Eric S. Johansson" <[email-masked]>
Date: Tue, 11 Mar 2003 13:46:48 -0500

> systems where the majority of email recipients are first-timers.

I stand corrected.

Let me rephrase my comment them.  The cost of sending e-mail on a low-end 
machine will probably the only about 30 or 40 seconds per address[1].  This 
charge will occur in background and not impact the user experience.  Obviously 
if someone sends a message to a large number of people, then it will take quite 
a while before the message will be delivered.  Assuming they are willing to or 
able to (because of power issues) keep the machine running long enough to 
generate enough stamps, but it shouldn't be a problem.  Additionally, it is 
possible for folks to offer to volunteer to generate stamps for these people if 
you should so wish.

---eric

[1] the reason for a per address stamp is that it keeps spammers from recycling 
stamps on multiple clients.

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From: Vernon Schryver <[email-masked]>
Date: Tue, 11 Mar 2003 14:34:57 -0700 (MST)

> From: "Eric S. Johansson" <[email-masked]>

>                             ...   The cost of sending e-mail on a low-end 
> machine will probably the only about 30 or 40 seconds per address ...

If a 25 MHz 80486 needs 30 seconds to compute a number, then a 3 GHz
P4 should need at most 150 milliseconds to compute the same value,
and probably less than 75 milliseconds.  The ratio of clock speeds is
only 120X but has lots of other fancy stuff to make computations to
faster, particularly when all of the values can fit in the P4's (or
P-III's) vastly larger caches.  (Never mind that the 486 had only the
off-chip caches).

150 ms, not to mention 75 ms is less than a single typical round trip
through the Internet.  Getting the banner from a target SMTP server
needs 2 round trips.  However, a serious bulk mailer will surely
overlap SMTP sessions.

A computer that is limited to sending 1 message every 150 ms will send
576,000 mail messages/day.  Such computers cost less than $600 in
single quantities from retail stores, and a fraction of that if you
are willing to build your own "blade-like" servers.  (Ok, you might
have to settle for 1 or 2 GHz CPUs that are only 90 times as fast as
low-end systems.)

One 5 KByte mail message in 150 ms needs about 40 KByte/sec of bandwidth
after you add SMTP, TCP, IP, and link-layer overhead.  

Six of those $600 computers from CircuitCity will saturate a T1
and pump 3 Mmsgs/day.

So where is the major cost of schemes like hashcash to spammers?

Vernon Schryver    [email-masked]
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