What is “smart foldering” vs “spam foldering”?

Smart foldering refers to intelligent categorization of mail that has passed spam filtering. Gmail's Categories (Primary, Social, Promotions, Updates) and Outlook's Focused/Other are smart foldering systems.

Spam foldering is placement in the junk or spam folder because the message was classified as unwanted. This is a negative filtering verdict.

The distinction is critical. Smart foldering is organization of wanted mail. Spam foldering is rejection of unwanted mail. A message in Promotions reached the inbox successfully. A message in spam failed filtering.

Users can configure smart foldering preferences, moving senders between categories. Spam verdicts require explicit user rescue actions to override.

Smart foldering is sorting the cargo after it clears inspection. Spam foldering is quarantining suspicious cargo.