This document outlines 6 threats to email marketing: 1) Purchasing email lists is technically illegal but many email service providers prohibit sending to purchased lists. 2) Building email lists properly leads to higher engagement and lower spam reports. 3) Avoid "red flag" spammy words that can flag emails as junk. 4) Gmail sorting puts emails into primary, social, and promotion sections. 5) Segment audiences and target customers to reduce unsubscriptions. 6) Younger generations prefer chatting over emails due to emails being time-consuming. The document stresses properly building email lists and avoiding spammy practices to make email marketing effective.