Cookie OK is a WordPress plugin by RavanH that places a notification above each page about cookie usage on your site through the CookieOK script by Digital Morphosis.
This plugin is designed to be less obtrusive than others. Visitors will see a small band above each page with a notice about cookies being used which they can accept, after which they will not see the notification any more. But even if they ignore the message, they will still be able to browse your site. Nobody will be blocked at any time.