Show HN: I built a 55K-word email marketing knowledge base and Claude Code skill

I co-founded SmartrMail (email marketing SaaS, 12K ecommerce customers, acquired 2022). When I left, I no longer had access to the sending data I'd spent years learning from, billions of sent emails, deliverability patterns, things that actually move email engagement Cos' I don't have this data anymore, I built the best thing I could to help with the email marketing I currently do: --- my research process Multiple sprints across all major email marketing topics. The crawler pulled 908 sources: Litmus, Klaviyo, HubSpot, Campaign Monitor, and Salesforce annual reports; practitioner blogs; academic research; platform documentation; Reddit threads; Shopify forums; and community discussions on X. From those, I extracted 4,798 discrete insights. Every claim that made it into the guide has a source. Anything that was unsourced opinion got cut. That produced EMB v4: Over 80k words across 16 chapters. After two editorial passes, cutting duplicates, consolidating overlapping sections, removing a