Double opt-in means that when someone signs up for a newsletter subscription, there must first be an automatic mailing sent to their inbox containing a confirmation link. The recipient must click this link to both confirm and activate their subscription. In doing so, the recipient confirms that their email actually exists, and that they want to receive mailings from you.
Why is double opt-in important?
There are several reasons why you should use the double opt-in.
Reduce spam complaints
Anyone who uses mailing lists to send out mailings will inevitably receive unsubscribes and spam complaints. Everybody hates spam and anything that resembles spam so even if you have a clear unsubscribe link in each mailing, there will always be someone that could click “report spam” via their email client. By using double opt-in, you can reduce these spam complaints to a much lower number.
Do you sell advertising space in your newsletter?
You might be able to boast to advertisers that you have a contact list of 20,000 addresses that you send to every week. But since you only use single opt-in, many of your 20,000 emails are actually incorrect or are delivered to people who are not at all interested in your mailing. The result? Your advertiser gets poor returns from their campaign and stops buying ad space.
If you instead had a much smaller contact base of 2,000 (double opt-in) addresses, your advertiser would get access to much more segmented audience with validated emails and actively interested subscribers. Your advertiser gets more clicks on their ad and a great return on their campaign resulting in them buying more ad space in your mailing.
Double opt-in benefits everyone so make sure you use it!
Future laws, rules and regulations
There is currently no law to use double opt-in but it will probably be in place within the next few years, so be proactive and start using double opt-in.