When someone opts-out of your email list, it’s hard not to take it as a personal insult.

But, it’s not always the slap in the face you think it is. Rather, an opt-out is an opportunity to learn, and to improve your email marketing. I won’t go as far as to say it’s a gift, but there definitely is value.

To start, know that you are not alone. Opt-outs happen to everyone. The average opt-out rate is about 2%, but it’s not about comparing yourself to others in your industry.

You can gain real knowledge by comparing opt-out rates from your own past sends. Comparing yourself to others gives you a ballpark idea of how you’re doing, but comparing against your own performance leverages your audience’s direct feedback about your activity.

If you see a spike in your opt-outs, that’s a clear sign of something, and not one that should be ignored. Think about your recent activity: Has something changed? Have you increased your sending frequency? Maybe your content is no longer relevant to your audience.

But opt outs are not always so black and white. It may not be as clear as increased sending, or irrelevant messages. That’s where opt-out comments come in. With Constant Contact, any time someone opts-out of your list, they are given the opportunity to say why they’re doing so. You can pull this report and hear directly why people decided to unsubscribe. You can then use this feedback to keep the remaining people on your list.

Of course, learning why customers opted out is great, but an opt-out doesn’t have to mean the end of the relationship. Someone opting out of your email list doesn’t automatically equate to them not wanting to hear from you. It could just be they get too many emails — and I’m sure we can all relate to that.

Email is one way for your organization to communicate. If your subscribers don’t have enough time to receive your emails, they can connect via Twitter or Facebook, or right on your website. By making sure you promote all the ways your customers can connect with you, you increase the chance they’ll continue the relationship post-opt-out.

The average list can deplete by as much as 30% every year. You can easily prevent his by monitoring your opt-outs and opt-out comments, and acting on them. Remember, instead of asking yourself, “How could they opt-out?” ask “Why did they?”

How do you learn from subscriber opt-outs? Share your thoughts in the comments below.