Foremost, the amount of spam hasn't reached my limit yet. Spotting
spam is effortless and easy to delete. I'm much more concerned about
the number of television programs I have to "filter" before I find
something good. (This really shows me to go back to a life without
it, but now I've risked being filtered for diverting from the topic.)
However, I understand that it is a big issue for some -- i.e. those
whose mailboxes are often near their storage capacity. Filling these
mailboxes with spam is akin to unintended denial of service. And to
some it's just a plain annoyance.
If we do choose to do more filtering, I agree with the many before me
who suggested a two-tiered solution -- moderating or challenging only
those who are not members of the list. In this case, I prefer the
challenge approach since it doesn't burden the administrator.
There are likely several technical and operational issues in the way
of such a solution. For example, many people have different
addresses for sending and receiving. I for one, receive from this
list at acm.org but ACM does not provide an outgoing service and thus
I cannot send from there. Likewise many servers add, remove or
change subdomains (or even domains, like after a merger) on the
There is likely technology to address some of these concerns, but as
with any technology, members need to be aware of what the potential
limitations may be. As others have stated, some of this technology
may not be available on the ACM server, and changing the address has
its own implications (though perhps we could change the ACM address
into some sort of alias).
Blocking entire domains, is problematic since both legitimate users
and spammers use the "free" mail servers. I know that the better
ones filter spam on the outgoing side, but others may not. I
wouldn't want to be caught in the wrong domain if I used a "free"
I certainly don't want to go down the path of closing the list to
non-subscribers, since every once in a while there is something from
a non-member which can be interesting or fruitful like a job opening.
Whether these are on- or off-topic is another story, but they don't
amount to very much mail (there's much more advertising spam), and
frankly I like receiving it.
In summary, if we have to block something, I'd support a challenge
system for non-members, as this would block most of those using
massive mailing lists, and allow those who are serious about getting
through to Ada advocates.