Many companies sell your email address when you unsubscribe. By unsubscribing you have established two things: 1. You are not interested in their product or se

Many companies sell your email address when you unsubscribe. By unsubscribing you have established two things: 1. You are not interested in their product or service (Obvious) 2. You read your mail, and it is not a throw-away box. (Non-Obvious) Unsubscribe and your email address suddenly gets commercial value that it did not have before.