perhaps, but the blacklists cause the opposite problem - they cause a
great deal of legitimate mail to not be delivered. IMHO the practice
of bouncing or dropping mail from blacklisted address blocks is about
as harmful to the reliability of email as the spam itself.
blacklists vary tremendously in intent and method of operation. it is
probably a bad idea to make a blanket statement like this.
I was talking about blacklists in general. There may be exceptions to
the rule. However I'm fairly convinced that spam is in the eye of the
beholder, so a blacklist only "does the right thing" if it uses the same
criteria as the recipient would like to use.
Note also that I didn't say that all use of blacklists was inherently
bad, but that using them to bounce or drop mail was harmful. There
are less drastic measures that would still serve to discourage spam.
Keith