To clean out bogus e-mail addresses and avoid spam traps, you need to define what an “inactive e-mail address” is for your company. And for every company, this definition differs. For example, if you are a marketer for a weather service that e-mails daily and 60 percent of your recipients click through your e-mail to your site, you may want to define “inactivity” as “no open or clickthrough in the last 30 days.” Alternatively, if you are a marketer for, say, a home goods catalog that e-mails monthly and has a lower clickthrough rate, you’d obviously want to come up with a looser threshold.
There are a number of easy and cost-effective ways you can build healthier houselists from the start:
Allow your customers to notice their own typos. One simple way to do this is to enlarge the size of the input box. A second way to allow customers to catch their own typos is to provide a confirmation page. You’d be surprised how many users actually will reread what they typed and correct any errors.
For lists that absolutely have to be perfect from the get-go, consider implementing “double opt-in.” Double opt-in means that after individuals register, you send them an e-mail with a special link that they must click through to join your mailing list. While this method can be highly effective, it is not always reliable, as it (a) is tricky to implement correctly and (b) can be frustrating for your users, resulting in registration abandonment. That said, for certain industries, such as financial services, double opt-in is highly recommended.
Make sure there is a clear value exchange and you provide sufficient reassurances regarding privacy. Users tend to enter bogus or secondary e-mail addresses because they see no upside to getting an e-mail from you. So make sure you send something your customers want to receive.