Toate browserele salveaza o copie cu paginile web care au fost vizitate recent. Cand repetam cautarea, informatia este primita de la copie mai degraba decat de la server-ul original(pentru a mari viteza de acces si pentru a reduce traficul). Caching-ul este facut de furnizorii de servicii, cat si de browser-ele utilizatorilor. Cachinul reduce audienta masurata pe un site, paginile si reclamele.
All Internet browsers, such as Microsoft Internet Explorer and Netscape Navigator, save a copy of all web pages that have been recently visited. On repeating the visit to the page, it is often retrieved from the cached copy rather than from the original server (to speed access and reduce Internet traffic congestion). Caching is carried out by service providers as well as by users' browsers. Caching reduces the measured audience to a site, its pages and its ads