Definition - What does Unsubscribe mean?
Techopedia explains Unsubscribe
One issue related to an unsubscribe method is the original opt-out method. This is often present when companies actually collect the data for email or service marketing, often in the form of a check box. One common question about a company’s opt-out is whether the form or other interaction contains a check box that a user must actively check to receive future communications, or whether the check box comes pre-checked, and will send out email marketing or other direct communications to a user as a default setting. Again, pre-checked boxes and other similar defaults can leave users with the feeling that they have been tricked into receiving email marketing or other communications.