Just under a year ago we made a small change to the Campaign Monitor subscribe forms to ensure they weren’t vulnerable to any nasty comment spam and other types of form spam. This was a pretty simple change and has certainly done the trick to date.
Having said that, there are still some old school single opt-in subscribe forms out there, some of which are capturing unwanted and bad email addresses. To prevent these annoying spammers from filling your lists with unwanted email addresses, we’ve just added an extra step in the subscribe process that only impacts these older forms.
This simple extra step is a small form that requires the subscriber to enter a 6 digit number, like the screenshot on the right. This way we can prevent spammy subscribers joining your list.
How to avoid this verification step
Again, this only affects older subscribe forms that were created more than a year ago and submit to the campaignmonitor.com domain instead of the cmail1.com domain.
If you’re a customer using this older subscribe form code, we recommend updating it to the latest version available in your account. As soon as you do this, this second step will be removed and your forms will continue working like they always have.
If you have any questions at all about this, please fire them our way.