You are an e-commerce and email marketing expert. Write a detailed, 2400-word guide on email for Etsy sellers. The guide must cover: 1) Building an email list (Etsy policies, lead magnets), 2) Welcome sequences for new customers, 3) Abandoned cart recovery for Etsy, 4) New product and collection emails, 5) Promotional emails for sales, 6) Customer appreciation and reviews, 7) Re-engagement for past customers, 8) Seasonal and holiday campaigns, 9) Metrics for Etsy sellers (sales, repeat customers), 10) Tools and platforms.