> Overall blacklists aren't that effective and cause a lot of false > positives. They may make sense in the case of something like > SpamAssassin which uses a blacklist in conjunction with other false > positives, but by themselves they really aren't a responsible way of > dealing with the spam problem. I think it's better to discourage "worst > practices" than to sucumb to plugin mania.
Blocklists aren't fundamentally broken, they are a tool which can be used properly or misused (just like many other tools). Many admins choose to maintain their own DNSBLs for one reason or another. It may be a way to control relay access based on their own subscriber IP addressess. At my site we keep a record of IPs that have persistently abused our site over the past few days. i.e. DNSBL != (SPEWS or MAPS or whatever)
