How do you keep those e-mails fresh? Send out a re-introduction mail. Remind your subscribers when and how they signed up for your list, and let them know you’re going to start sending them mail again, and what to expect. Make it easy to opt-out if the subscriber doesn’t want your messages anymore, or even start fresh and offer the option to opt-in to a new list instead.

We’re just tackling this very issue ourselves right now. We’ve been offering a “subscribe to our e-mail newsletter” checkbox on the signup form of one of our websites for the past 3 years, but haven’t sent a mail in a few months. To make sure we only have an active list of interested users, we just sent a short message out to the list letting them know we’re going to send some news their way soon, and offered a chance to unsubscribe if they’re not interested anymore.

Do you still want to hear from #SITENAME#?

Hello #FIRSTNAME#,

You signed up with #SITENAME# back on #SUBDATE# and requested our email updates. We haven’t mailed you in a while, and want to make sure you’re still interested in receiving news from us. We’ll have a great new site launching this month we want to tell you about, for example, as well as some #SITENAME# news. We don’t want to send you e-mails you don’t want, so feel free to change your mind and unsubscribe with the link below. You won’t receive another e-mail from us again.

#UNSUBSCRIBE LINK#

#SIGNATURE#

The friendly reminder is much less likely to evoke a negative reaction, and gives us the opportunity to clean up the list before sending out full-blown newsletters again.