Cache-busting is the process by which a page content is served in such a manner as to prevent the element to be served from a browser or proxy cache. It prevents the browser or proxy from reusing an element it has already loaded and cached and forces it to always fetch the file from the server. Cache-busting is mainly used for ad serving to ensure that the same ad is not always served behind a proxy or within a browser. Cache-busting is also used for counting ad impressions.
Cache-busting is achieved by the way of a cache buster placed at the top of the page or directly in the ad tag to make the browser think that every time it is fetching a new file.
According to the same principles, cache-busting is also used for web analytics.