When you run an email list, there are some subscribers who don't open your emails. This could be because they aren't interested in your offer. But since they signed up to receive your content, it's more likely that they simply missed it or it went to their spam folder. A good way to boost engagement on your list is to resend unopened emails.
Autoresponder programs like MailChimp have features that allow you to resend unopened messages. If you have an important message that your subscribers didn't open, you can resend it the next day and bring it to their attention.
One word of caution about resending is that it can appear spammy. For this reason, you should resend sparingly or only do it once. Try resending on the next day to give people enough time to see the original one first.
For example, you might send an email announcing your latest blog post. While 40% of your subscribers opened it, this means 60% didn't. This is an especially good piece of content and you feel it's a shame for more than half of your subscribers to pass it by, so you decide to resend.
How to Refresh Resent Emails
The trick here is to change the subject line of your email. It's possible that your subscribers passed over it as they skimmed their inbox because the subject line wasn't compelling enough to hook them. With a new and slightly different subject line, you increase the changes that these readers will check it out.
This will increase your open rates and hopefully drive more traffic to your blog. It can also help to build deeper relationships with your readers. They may have missed a piece of valuable content which will help build this relationship.
Segmenting Your List
Your unopen rate can also be used to segment your list. If there are subscribers who consistently don't open your messages, they may be unresponsive or you may have a bad email address. Remove these subscribers from your list. This is called keeping a “clean” list and it improves the performance of your email campaign.
There are some marketing studies that question this approach. After all, if you resend every single email, you're cramming your subscribers' email inboxes even fuller with messages. Your autoresponder program gives you statistics that show the results of your efforts. Rely on these metrics and see how many of your subscribers are opening the second emails. If you're seeing high open rates, keep doing it. If not, stop.