Okay, you tried to save the customer e-mail relationship. You know you are about to lose them. There is one more trick to try: ask them if they want to leave.

But do it right, says Morgan Stewart, principal, at ExactTarget's research and education group. "Give them a choice of two options: one will opt them out completely, the other will continue the relationship if they want. Most people end up clicking yes, they want to continue," he says.

It is a misconception is that if you only offer a 'Yes, please subscribe me' option that more people will react positively by opting into the program, he writes in a blog post. "We have tested using a single "Yes" option vs. the "Yes and No" options for at least 6 different clients. In every instance the "Yes and No" option resulted in significantly more opt-ins! There is something about seeing both options that drives more people to respond. Maybe these emails seem like less of a gimmick, more genuine, or more serious."

Also, he writes, remember to:

Be clear in the subject line. Email subject lines like, "Verify your subscription continue receiving [XYZ]" or "Your subscription will end soon" tend to work well.

Restate your value proposition. "A concise restatement of what your subscribers can expect reminds them of what you are all about… and what they will miss if they do not confirm their email subscription."

Send a second request. "We find that these second requests consistently get nearly the same number of opt-ins as the first, so failing to do so could have a material impact on the success of your campaign. We have worked with organizations that have tried a third request using the same logic, but the dropoff at this points has been substantial in our experience - two appears to be the right number."

Also read in this special report: Read Digital Body Language to Stop an Unsubcribe and How to Salvage an Unsubscribe.