A web beacon is a clear picture file used to keep track of your navigation through a single website or a series of websites. Web beacons also go by the name of web bugs and are normally used by websites that use third party traffic monitoring and tracking services.
@frankdevineMay 21.2013 — #Also called a Web bug or a pixel tag or a clear GIF. Used in combination with cookies, a Web beacon is an often-transparent graphic image, usually no larger than 1 pixel x 1 pixel, that is placed on a Web site or in an e-mail that is used to monitor the behavior of the user visiting the Web site or sending the e-mail. When the HTML code for the Web beacon points to a site to retrieve the image, at the same time it can pass along information such as the IP address of the computer that retrieved the image, the time the Web beacon was viewed and for how long, the type of browser that retrieved the image and previously set cookie values.
Web beacons are typically used by a third party to monitor the activity of a site. A Web beacon can be detected by viewing the source code of a Web page and looking for any IMG tags that load from a different server than the rest of the site. Turning off the browser's cookies will prevent Web beacons from tracking the user's activity. The Web beacon will still account for an anonymous visit, but the user's unique information will not be recorded.