When the HTML code for the beacon points to a site to retrieve the image, at the same time you can transmit information such as the IP address of the computer that retrieves the image, how long the beacon was viewed and for how long or the type of browser that retrieves the image.
Uses of the beacon
Also known as web bugs, beacons are often used by a third party to monitor a site’s activity. Thanks to this we can later carry out more precise analyses. A beacon can be detected by viewing the source code of a web page and looking for any IMG tags that are loaded from a different server than the rest of the site. Disabling a browser’s cookies will prevent the beacon from tracking user activity. This will be represented as an anonymous visit, but the user’s unique information will not be recorded.
How beacons work
Originally, a beacon was a small clear GIF or PNG image, or an image of the same color as the background, usually 1 x 1 pixel, that was embedded in an HTML page, usually a page on the Web or the content of an email. Modern beacons also use IFRAME, style, script, input link, embed, object, and other tags to track their usage. Every time a user opens a page with a graphical browser or email reader, this image and other information is downloaded. This download requires the browser to send a request to the server that stores the image or information, allowing the organization running the server to keep track of the HTML page.