By Karen J. Bannan
Story posted: October 29, 2009 – 11:58 am EDT

Marketers generally are pretty good about removing bad e-mail addresses-unsubscribes and addresses that bounce-from their lists. But what about people who haven’t opened a message in, say, more than six months? While it’s tempting to just let them be, it’s not a good strategy, said Luke Bone, media director for interactive agency Tocquigny.

“Marketers are often judged by the size of their lists, which is one reason why they don’t prune as often as they should,” he said. “But it’s far better to have the best, most engaged list possible.”

Bone provided these suggestions for making that goal a reality:

Check your database. One of the main reasons recipients stop clicking on e-mails is that they are no longer prospects. They don’t need white papers that can help them make a purchase; they need content that helps them use the marketer’s products more effectively. Marketers should periodically go through their databases, pull out prospects that have converted and move them into a customer e-mail segment. “This is why it’s important to have a database and process where you can identify the source of an opt-in and match those addresses to sales and marketing activities,” Bone said.

Isolate them. Take all inactive addresses and put them into their own segment. “You’re going to have to get microfocused with this segment,” he said. For example, are any folks on the list forgoing the newsletter but still spending time on the Web site? Looking at Web analytics may help a marketer determine this.

Change it up. If you’ve been sending out links to white papers, consider offering nonresponders alternate content, such as webinars, podcasts or a simple newsletter. “You can also do more obvious things like changing the time and day you’re sending out messages,” Bone said. Or, he added, send out a survey or a link to ask people to re-opt in.

Be obvious-as a last-ditch effort. “Change the subject line to We miss you’ or Please come back,’ ” Bone said. “Sometimes that’s enough to get someone clicking through.” Once they open the message, ask them to update their preferences for content, frequency or types of offers. Marketers can also ask recipients to follow them elsewhere. A customer or prospect who is on LinkedIn, for instance, may prefer to follow the marketer’s movements in a LinkedIn group.

If you’re still not seeing results, cut ’em loose. “People are getting laid off. Addresses may not be deleted, but there’s no one there anymore,” Bone said. “It all goes back to the quality of your database and your list cleaning best practices.”

All great tips from BtoB Magazine. Do you have other email list maintenance ideas? Please share.