What cookies are
A cookie is a small text file that a website asks your browser to store on your device. When you return to the site, your browser sends that file back, which lets the site recognise your visit. Nothing in a cookie runs on your computer, and a cookie cannot read other files on your device or pick up your email address on its own.
Some cookies are essential for the site to work at all. Others are optional and help us understand how the site is used, so we can tell which guides are useful and which need rewriting. Where a cookie is optional, we describe it in the next sections and explain how to remove it.
Good to know
Cookies are not the same as a virus or a program. They are plain files of text, and you can open or delete any of them from your browser settings at any time.