Despite choosing single opt-in over double opt-in for many years, I am still surprised to see MailChimp take this step. This is the email they sent me. We’re making important changes to the signup process Starting October 31, single opt-in will become the default setting for all MailChimp hosted, embedded, and pop-up signup forms. This change will impact all MailChimp users, so here’s everything you need to know: All MailChimp signup forms—including all of your existing forms—will shift from double opt-in to single opt-in. This change will occur automatically; you don’t need to make any manual adjustments within your account. The overall signup process will change: when single opt-in is enabled, the opt-in confirmation emails and the signup thank you page will not be sent or displayed. If you wish to keep your existing forms as double opt-in, you will need to set your preferences here before October 31. Moving forward, you'll have the option to enable double opt-in within your account’s list settings.