Unlike other security technologies that release a new rule or processing logic against a new threat and then rescans all messages, Cloudmark ActiveFilter’s patent-pending message filtering technology simply changes the classification of an existing fingerprint from legitimate to spam or virus. Since service providers only need to take targeted action on individual messages that have changed classification, there's little impact on resources.

Cloudmark ActiveFilter achieves its efficiency through Cloudmark's Advanced Message Fingerprinting technology that reduces a spam message to a lightweight set of "fingerprints" — a unique abstraction of the message. Cloudmark ActiveFilter caches fingerprints that have been scanned and delivered to the mail store while also continually monitoring for new fingerprint updates from Cloudmark's Global Threat Network. If there's a match between a newly-identified spam fingerprint and a message in the mail store, Cloudmark ActiveFilter notifies the mail store to take action on just that specific message.