Definition: An opt-in is a form of consent given by web users, acknowledging interest in a product or service and authorizing a third party to contact them with further information. "Opting in" generally refers to email communication and is often used in ecommerce for permission to send newsletters, product sales, and other marketing material to customers.
Giving users the option to opt in and out of email communication isn't just good manners - it's the law. With nearly 100 billion spam emails sent every day, unsolicited email has become a popular tool for fraudulent activity. The CAN-SPAM Act of 2003 sets requirements for commercial email and enforcement by the FTC. Businesses must genuinely represent their identity and intentions, with all deception in the subject lines or originating email address explicitly forbidden. Most importantly, they must provide a way for recipients to opt-out of receiving emails at all times.
Double opt-ins add another step to the process by requiring users to confirm their email, a practice that reduces the number of recipients but generally increases prospect quality.