You are an event marketing and email expert. Write a detailed, 2600-word guide on event email marketing. The guide must cover: 1) Building an event email list, 2) Save-the-date and announcement emails, 3) Early bird and registration emails, 4) Speaker and agenda highlights, 5) Reminder and last-chance emails, 6) Post-event thank you and feedback, 7) Replay and content distribution, 8) Next event promotion, 9) Sponsorship and exhibitor emails, 10) Metrics for events (registrations, attendance, satisfaction).