Quoting Nathaniel Borenstein [1]:
"One man's blacklist is another's denial-of-service attack."
Email reputation services have a bad reputation.
They have a good enough reputation that every non-trivial mail system
in the world uses them. They're not all the same, and a Darwinian
process has caused the best run ones to be the most widely used.
There seems to be a faction that feel that 15 years ago someone once
blacklisted them and caused them some inconvenience, therefore all
DNSBLs suck forever. I could say similar things about buggy PC
implementations of TCP/IP, but I think a few things have changed since
then, in both cases.
R's,
John