DNSBL – Spam Cop

This list is maintained at http://www.spamcop.net/bl.shtml

Their policies are here. Roughly, the list both accepts nominations and maintains spamtraps.

In their own words …

However, it should be noted that SpamCop is aggressive and often errs on the side of blocking mail – users should be warned and given information about how their mail is filtered. Ideally they should have a choice of filtering options. Many mailservers can operate with blacklists in a “tag only” mode, which is preferable in many situations.