Cookies are small files used by websites to improve their visitors' browsing experience.
Browser cookies retrieve data that informs the website about the previous activity conducted on the site by particular visitors. Web browsers that support cookies have been developed since the mid-1990s. Cookies serve a variety of purposes, from remembering visitor preferences when they browse a site to keeping a secure session secure and encrypted.
Third-party tracking cookies are controversial due to their online behavioral tracking functions. Add-on modules and components can be installed in Web browsers to block some of these tracking cookies. Privacy advocates argue that cookies are highly intrusive since they are stored in the hard drives of visitors' computers, often without their knowledge.