It is a difficult problem and I don't have a magic bullet, but I think
that things can be done. The root of the problem is economic. Spam is
about five or six orders of magnitude cheaper the paper junk mail for
the sender.
Once we get past the various notes that observe how serious the problem is,
most attempts at solution in fact DO seek a magic bullet. A single
mechanism that will "fix" the problem.
It won't happen that way. It can't. The nature of spam is far too complex
and diffuse.
Spam is like roaches. Using a number of techniques, it can be reduced to a
manageable level, but it cannot be eliminated.
We need to start thinking in terms of a broad suite of mechanisms across
the full range of the email system. And the key word is system. Lots of
parts.
We need to put different types of mechanisms in different places in the
system. Some at the receiver MTA. Some at the receiver ISP. Some at the
sending side. Some cooperative. Some by fiat. Some precise. Some
heuristic. Some in the courts. Etc.
Of course, all this would be greatly helped by having a clear, firm and
precise definition of spam. One that has some utility. A definition that
is often used is "whatever the receiver does not want to receive." That
one ain't useful.
And through all of this, we need to observe that the technical
characteristics of spam messages and spam traffic are identical with valid
(bulk) subscription mail. And I do mean identical. And subscription mail
is the stuff that receivers DO want to get. And waving a magic wand,
claiming that whitelists solve that issue, again misses the point.
This is a complex problem and it is not amenable to a simple
solution. However it IS likely to be amenable to some technical work and
it would be worth looking for mechanisms to standardize, to give better
leverage for spam control.
d/
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Dave Crocker <mailto:dave(_at_)tribalwise(_dot_)com>
TribalWise, Inc. <http://www.tribalwise.com>
tel +1.408.246.8253; fax +1.408.850.1850