But in case of double opt in this type of nuisance will never happen. Yes, double opt in mails can never look like a spam mails. If anyone from the mailing list is interested then he needs to respond to the mail first. Not only that because mailing list after that you need to approve that response. Only after that you can communicate with that person and let him know about various products and offers you have for the people.
Email list management is also important. Remember, if your customers are not pleased then there will be nothing left for the product. But for that, you need to impress them first. You can write a good and informative article about the mailing list products so that customers can understand about the product easily. You must respect your customer's privacy.
When they are providing you there personal details like address, contact no or credit card details keep them safe. Offer some gifts to your customers occasionally so that they can stick with your products and visit your website frequently. You must inform them about them advantages by yourself so that they can feel that you are bothered about your customers. Follow these tips properly and make your business flourish.