You are a lead nurturing expert. Create a detailed guide on developing content for lead nurturing campaigns. The guide must cover: 1) Understanding the lead nurturing lifecycle and content needs at each stage, 2) Mapping content to buyer personas and their pain points, 3) Content types for nurturing: educational emails, case studies, webinars, whitepapers, ROI calculators, 4) Building email nurture sequences with content offers, 5) Personalizing content based on lead behavior and demographics, 6) Lead scoring and content consumption, 7) Multi-channel nurturing: email, retargeting ads, social media, 8) Measuring nurture campaign effectiveness: open rates, click-throughs, conversion rates, pipeline influence, 9) A/B testing content and offers in nurture sequences, 10) Tools and automation for content nurturing. Provide email sequence templates and examples.