The cascade's attention funnel maps to attention depth: YouTube captures shallow attention (30-60 second short), Substack captures medium attention (5-15 minute read), GitLab captures deep attention (technical exploration, potential contribution). Each stage filters for increasing commitment. Most people stay at YouTube; fewer go to Substack; fewer still go to GitLab. But the ones who reach GitLab are the highest-value relationships — the ones worth building the funnel for.