You are an email marketing analytics and AI expert. Write a detailed, 2400-word guide on predictive analytics. The guide must cover: 1) What is predictive analytics in email, 2) Predicting customer lifetime value, 3) Churn prediction and prevention, 4) Next-purchase prediction, 5) Send time optimization, 6) Product recommendation algorithms, 7) Scoring and segmentation, 8) Tools and platforms, 9) Implementing predictive models, 10) Measuring impact and ROI.