How does Gmail’s “Categories” tab fit into filtering?

Gmail Categories organize messages that have already passed spam filtering. The tabs (Primary, Social, Promotions, Updates, Forums) are a sorting mechanism, not a spam verdict. All categorized mail is in the inbox.

The Primary tab holds personal correspondence. Social collects notifications from social networks. Promotions gathers marketing emails. Updates captures transactional messages like receipts and confirmations. Forums holds mailing list discussions.

Landing in Promotions is not a deliverability failure. The message was delivered to the inbox and categorized appropriately. Many marketers mistakenly treat Promotions placement as spam, but recipients who want promotional content know exactly where to find it.

Gmail uses machine learning to categorize messages based on content patterns, sender type, and user behavior. Users can train the system by dragging messages between tabs.

Categories are the different piers in the harbor. Every ship docked there has arrived safely.