Unsubscribing in 2007 Marketers Can Get More Out of Goodbye

I thought this article had some interesting points:

Why scrutinize unsubscribe practices? Because providing a method for subscribers to leave your mailing list is a crucial component of email marketing, contrary to almost any other form of marketing and advertising.

• Consumers who don't trust your unsubscribe process are more likely to report you to their ISPs as a spammer.
• The unsubscribe process itself is a rich vein of information about how your subscribers are thinking, how they see your company and what they want from you.
• Having a workable, trustworthy unsubscribe process can even retain a customer for you if you give them other options.