A cookie is a small file which asks permission to be placed on your computer’s hard drive, and allows web applications to respond to you individually. The application can tailor its operations to your needs, likes and dislikes by gathering and remembering your preferences.
As such, cookies can help to provide you with a better browsing experience, but they do not provide third party access to your computer or provide any information about you, other than the data you choose to share.
Most web browsers automatically accept cookies, but if you prefer you can usually modify your browser settings to decline cookies. This may prevent you from taking full advantage of some websites.