Duly noted… I erred in a column I wrote today for BtoB E-mail Marketer Insight. I also published it in Are you getting an “F” in email marketing? in this week’s issue of WordBiz Report. (Article since revised.) Collecting email addresses with a double opt-in sign up process is *not* a requirement of CAN-SPAM regulations. It is, however, an email marketing best practice. Double opt-in means that new subscribers must confirm their opt-in to your list by replying to an automatic confirmation message sent by you. Inside the message is a uniquely coded link. This does two things: it reassures your new subscribers that they have indeed signed up. And it tells you that you’ve collected a new, valid email address. Thanks to several astute readers who pointed out my error.