One of your goals for your online business is to put your products into the hands of the people most likely to buy it. You've written stellar sales copy, and your product is unique and highly desirable, so why waste your time and effort trying to reach people who have shown no interest in it? Random email lists have response rates as low as 1%, and some lists never generate a click-through' to your site. Purchased opt-in lists, on the other hand, can generate a 10% visit rate, or higher. It makes good business sense to reach the right people with opt-in lists.