What are cookies?

Cookies are harmless text files that web servers can store on your computer's hard drive when you visit a website. They allow the server to recognise you when you revisit. 

There are two main types:

Transient (or per-session) cookies

These only exist for the duration of your site visit and are deleted on exit. They recognise you as you move between pages, for example recording the items you add to an online shopping basket. These cookies also help maintain security.

Persistent (or permanent) cookies

These stay on your machine until they expire or are deleted. Many are built with automatic deletion dates to help ensure your hard drive doesn't get overloaded. These cookies often store and re-enter your login information, so you don't need to remember membership details.