Cookies are small files that are used by websites for a wide variety of purposes. Some help websites perform properly, such as keeping you logged into a site. Others collect information on your browsing activities within a website or more generally across the internet.
You can control the type of cookies permitted onto your computer through the settings or preferences of your browser. There are also programs available to control cookies, and these often come in the form of an extension or add-on to your browser. More information (from allaboutcookies.org) >