The term opt-out refers to several methods by which individuals can avoid receiving unsolicited product or service information.
[1] The UK's Direct Marketing Association operates a voluntary opt-out scheme through the Telephone Preference Service, which was established in 1995.
In order to be included on the register, a telephone number must be used or maintained primarily for private or domestic purposes, or exclusively for transmitting and/or receiving faxes.
By capturing data generated by website and landing page visitors, advertisements are placed so as to reach consumers based on various traits such as demographics, psychographics, behavioral variables (such as product purchase history), and firmographic variables or other second-order activities which serve as a proxy for these traits.
Wi-Fi-based positioning systems take advantage of the rapid growth of wireless access points in urban areas and are used by companies like Google, Apple, and Microsoft, to obtain data about their customers' locations, in order to provide a better service.
However, some users have expressed concern about their privacy being affected by this type of unsolicited positioning system, and have asked for opt-out alternatives.
Google suggested the creation of a unified approach for opting-out from taking part in Wi-Fi-based positioning systems.
Suggesting the usage of the word "_nomap" (Underscore and nomap) append to a wireless access point's SSID to exclude it from Google's WPS database.