eBooks are effective in email marketing because they offer substantial, in-depth information that can educate and engage your audience. Here are some reasons why eBooks are beneficial: - They provide value to your subscribers, which can increase trust and loyalty. - eBooks can position you as an authority in your niche. - They can be used as a lead magnet to grow your email list. - eBooks can be repurposed into blog posts, social media content, and more.