What this is
This is a knowledge bundle in Open Knowledge Format (OKF) v0.1, an open, vendor neutral specification published by Google Cloud in June 2026. OKF represents knowledge as a directory of markdown files with YAML frontmatter. Every file is a concept. The file path is the concept identity. Concepts link to each other with ordinary markdown links, which turns the directory into a graph. There is no required tooling: if you can read a markdown file, you can read this bundle, and if you can clone a git repository, you can ship it.
Conformance
Every concept file carries a frontmatter block with a required type field, and usually title, description, tags, and timestamp. The reserved filenames index.md (a directory listing for progressive disclosure) and log.md (a chronological change history) appear at the bundle root and in some subdirectories. Cross links are bundle relative, beginning with a slash. Attribution lives in each concept’s Citations section rather than in a single frontmatter resource.
Broken links are intentional
Broken links are permitted by the spec and simply mark knowledge not yet written.
Where the content comes from
This is a general practitioner reference for email, lifecycle and CRM marketing, synthesised from authoritative sources rather than copied from any single one:
- Standards and regulators for the mechanics and the law: the IETF RFCs, Apple and Google platform documentation, and the FTC, ICO, and FCC.
- Recognised industry and research sources for the practice: deliverability, design, benchmark, and measurement references such as Litmus, Campaign Monitor, Klaviyo, HubSpot, Baymard, Word to the Wise, and the academic literature on extraction, bandits, and uplift.
- The platform behaviours, research, and regulations these draw on are mirrored into references as first-class concepts, with the specific sources cited in each concept.
How to navigate
The bundle is organised around the work: the principles that set the stances, the foundations that hold the cross-channel operations (data, segmentation, lifecycle, content, automation, tooling), the channels you send through, and the measurement layer that proves incrementality and sizes experiments. The references hold the external platform behaviour, research, legislation, and a glossary. The root index maps the lot; start with the layer your question sits in and follow the cross links.
Citations
[1] Introducing the Open Knowledge Format [2] OKF v0.1 specification