Many email services and Internet Service Providers (ISPs) detect the response of an email’s recipient to gauge whether the email is legitimate or not. Whether a recipient opens, clicks, replies, unsubscribes, forwards or deletes the message determines whether the message is considered as 'good’ or as 'spam’. Gmail, for example, ranks the importance of an email based on the recipient’s action - if the recipient replies, Gmail is more likely to class the email as 'important’. If your recipient can’t reply, your emails are likely to end up in the Spam/Junk folders (read more about keeping your emails out of spam in an earlier post).
