How does Outlook’s Focused Inbox differ from spam filtering?

Outlook Focused Inbox divides the inbox into two views:

Focused: Messages Outlook predicts are most important based on user behavior and sender patterns.

Other: Lower-priority messages including bulk mail and newsletters.

Spam filtering is separate and happens before Focused/Other classification. Spam-filtered messages never reach either inbox view.

Landing in Other means you passed spam filtering but were classified as lower priority. It is still successful delivery.

Focused Inbox is the express lane at port. Other is the standard queue. Neither is impound.