Do spam filters learn over time?

Yes, modern spam filters are built to learn continuously. They use machine learning models that update based on new data, user feedback, and emerging spam patterns. The filters you encounter today are smarter than they were last month.

When users mark messages as spam or move them out of the junk folder, those actions become training signals. Providers like Gmail and Outlook aggregate this feedback across billions of users to refine their models. A sudden spike in spam reports for a particular sender triggers rapid adjustment.

Filters also learn from spammer behavior. As attackers evolve their tactics, filtering systems detect new patterns and incorporate them into their detection rules. This creates an ongoing arms race between senders trying to reach inboxes and filters trying to protect them.

The harbor defenses are not static walls but living systems that grow stronger with every attempted breach.