What can be an effect of sending emails without permission?

Sending emails without permission can significantly increase the chance of those emails being marked as spam. When recipients receive unsolicited emails, they are more likely to perceive them as intrusive or irrelevant. Consequently, they may choose to mark those emails as spam, which can harm the sender's reputation and deliverability.

Moreover, email service providers closely monitor spam reports to protect users from unwanted messages. High rates of spam complaints can lead to the sender’s emails being filtered or blocked altogether, drastically reducing the chances of future emails reaching intended recipients. This can also impact the overall sender's domain and email deliverability rates, making it harder to reach engaged audiences in future campaigns.

In striking contrast, obtaining permission from recipients typically leads to a more positive outcome, such as higher engagement and loyalty, because the audience has expressed interest in hearing from the sender.