[Nottingham] Challenge-Response systems

Martin Garton martin at stupids.org
Fri Nov 4 12:13:10 GMT 2005

On Fri, 2005-11-04 at 11:44 +0000, Martin wrote:

> There's some pain somewhere to circumvent spam. The question is how much 
> and where. Are there any truly good solutions?

No perfect solutions,  but solutions that take to form "save my time,
but use up time of others" are impolite. It sends the message "my time
is more important / expensive than yours"  They might be right, or there
might be good reasons or excuses for sending that message, but the
message remains.

I agree that publicly available addresses will get more spam, but if
linux-kernel can manage to remain a non-subscription list and still
accept almost no spam then anyone can do it.

The main reason I wouldn't use a CR system isn't related to their
ability to prevent spammers getting through. That much is easy to
measure and may work to some extent.  I worry more about preventing
legitimate emails getting through. And before anyone says "but they do
get through, I receive them!" I am not talking about those where the
challenge was responded to correctly or even those which were manually
accepted by the recipient.  I am talking about the next legitimate email
that doesn't even get sent because of objections in principle to CR
systems by the sender.  That effect is hard to measure.


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