The Biggest Lesson Neil Learned From Sending Out 255 Million Emails

Executive overview

Sending generic emails to an entire list used to work. It no longer does. Audiences now expect relevant, segmented content as the default — irrelevant emails simply don't convert.

Segmenting your email list by interest or behaviour generates ~57% more revenue than sending the same message to everyone.

Why generic email stopped working

• Audience expectations have shifted: relevance is now the baseline, not a bonus
• Subscribers share a broad interest (e.g. marketing) but have distinct sub-needs: e-commerce, SEO, paid ads, social growth
• Sending one message to all of them suppresses opens, clicks, and conversions

How to implement segmentation

• Identify which pages subscribers opted in from — this signals their interest
• Build separate lists per topic or intent
• Write custom emails for each segment rather than adapting a single template
• Use AI tools (e.g. ChatGPT, Bard) to scale custom email creation across more segments

Where email is heading

• Dynamic content insertion: AI assembles personalised email blocks based on individual interests
• In-email commerce: select a product, choose a size, and check out without leaving the email
• Knowing subscriber behaviour (purchase history, browsing habits) enables Amazon-level personalisation