now private, invite-only
00_DOMAIN_BLACKLISTS
http://rfc-clueless.org/
+ lists domains that do not adhere to common best practices or requirements
+ does NOT list spammers!
+ listing criteria are explained well
+ http://rfc-clueless.org/pages/listing_policy
+ return codes are explained
+ http://rfc-clueless.org/
+ usage policy is not so clear but the FAQ implies that it’s just free to use for everyone
http://spameatingmonkey.com/lists.html
http://uribl.com/
http://wiki.junkemailfilter.com/index.php/Spam_DNS_Lists