Often, websites need to maintain information as you move from page to page, and possibly between your browsing sessions. For example, you expect, when moving between pages in a web shop, that the site will keep track of the contents of your shopping basket. If you have logged in, you expect the site to recognise you on each subsequent page. Cookies are used to meet these expectations.

Cookies are small pieces of identifying information, stored by your browser on your PC, to enable such information about your session to be maintained. The cookie may contain actual information (e.g. the date of your last visit), or just a unique reference ID that allows the site to look up (for example) the contents of your shopping basket in its databases.

If a site sets cookies routinely, these can also be used to track your successive page views, and therefore your behaviour on the site, whether or not you are logged in. Unless you log in or complete an enquiry form, such use of cookies will not enable the site to identify you (because cookies can only give access to information that the site already has). St. Mary's Church, Riverhead will not attempt to identify you unless you log in.

Cookies set by one site cannot be read by another. However, one web page may be made up of components (such as news stories, images or advertising), some of which are delivered from third parties. Each of those third-party sites will be able to set and read its own cookies on any page where its content appears

The site AllAboutCookies [opens in new window] provides independent information on cookies, and how to block them in specific browsers.