A new law came into force on May 26th 2011 in the UK and Europe that affect websites and how they deal with the user flow of saving cookies to a visitors browser.
Previously websites could use cookies as much as they liked and we only limited by the browsers of the people visiting their websites, but as of late May the Privacy and Electronic Communications (EC Directive) Amendment Regulations 2011 require that certain information must be given to that site’s visitors and the user must give his or her consent to the placing of the cookies.
In english, that means that a site must ask all users permission before saving a cookie to their browser.