Good explanations have a source.
The primary references behind the email concepts in this library.
Primary references used in the guides, checked while preparing this edition on September 11, 2026. Provider instructions can change. These links support the identified concepts, not a claim that any visitor’s account has been assessed.
Gmail: create and manage labels
Supports the Gmail-specific explanation of labels and their distinction from folders. The Action, Waiting, and Reference workflow is an original suggestion.
Open the primary reference ↗ Read the related guideGmail: avoid and report phishing
Supports the concepts of deceptive requests, independent verification, provider warnings, and phishing reporting. Fictional scenarios are illustrative.
Open the primary reference ↗ Read the related guideApache SpamAssassin: configuration reference
Supports the example of configurable rule scores, thresholds, and learning settings in one documented filtering system—not every provider.
Open the primary reference ↗ Read the related guideGoogle Developers: classification thresholds
Supports classification thresholds, false positives, false negatives, and the confusion-matrix concepts. Our score scale and numerical exercise are invented examples.
Open the primary reference ↗ Read the related guideGmail: create rules to filter your emails
Supports the Gmail-specific process for creating and managing filters. The label-first testing routine is a suggested workflow.
Open the primary reference ↗ Read the related guideGmail: email sender guidelines
Supports SPF, DKIM, DMARC, and provider-specific sender guidance. The article’s deployment-planning questions are original suggestions.
Open the primary reference ↗ Read the related guideGmail: report and correct spam
Supports Gmail spam correction, blocking behavior, warning explanations, and escalation for organizational policies.
Open the primary reference ↗ Read the related guideGmail: unsubscribe from an email
Supports Gmail’s unsubscribe interface and its description of mailing-list changes. The broader cleanup framework is an original suggestion.
Open the primary reference ↗ Read the related guideGoogle Account: make your account more secure
Supports account-security review areas including Security Checkup, software updates, unique passwords, and unnecessary app access.
Open the primary reference ↗ Read the related guideGmail: archive messages
Supports Gmail’s archive behavior, All Mail availability, and the return of archived conversations when replies arrive. The weekly routine is an original proposal.
Open the primary reference ↗ Read the related guideMicrosoft: spam confidence level (SCL)
Supports the provider-specific point that an SCL value alone no longer determines the cloud spam verdict or action; categorization and other signals matter. This is not interchangeable with our fictional 0–100 scale.
Open Microsoft’s SCL documentation ↗ Read the scoring overview