As a webmaster who is involved in sending marketing emails to customers, it is rightly believed that we should make it as easy as possible for recipients to unsubscribe from our maillist. Not only is it in the interests of the recipient who will get a much better impression of your website/company if you do, but as an email sender it also helps you keep a good quality maillist full of people who actually want to read and response to your mailouts, and helps you stay off blacklists.
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