Marvin Modules: DCC

DCC (the Distributed Checksum Clearinghouse) is a network of servers that keep a large database of spam fingerprints. When you turn on DCC, a fingerprint of your e-mails will be compared to the fingerprints of known spam. The more times that a message is reported to the DCC servers, the higher it's count. If the count of a message is greater than or equal to the values you choose below, it will be blocked.

Here is what the interface looks like: