The cookies used on our websites are classified based on the International Chamber of Commerce (ICC) guide for cookie categories. There are four broad groups of cookies.
By using cookies, a site 'knows' that you have been there before, and in some cases, tailors web content to take account of this based on what you have looked at or done previously. For instance, it can be helpful to vary content according to whether this is your first ever visit to a site - or if you are a regular website visitor.
Some cookies are more sophisticated. They might record how long you spend on each page on a site, what links you click, even your preferences for page layouts and colour schemes. They can also be used to store data on what is in your 'shopping cart', adding items as you click.
Almost all web browsers allow you the option to block cookies. That means you can block all cookies or you can choose which ones to accept.
This can however make browsing difficult - some sites do not work or work less well with cookies turned off. For instructions on how to manage your cookie privacy setting in your browser see this guide wikiHow - How to Clear Your Browser's Cookies.