Cookies for Comments is a WordPress plugin designed to enhance comment moderation by utilizing cookies to distinguish between legitimate users and potential spam bots. This tool adds a stylesheet or image to the blog's HTML, which, when loaded, drops a cookie in the user's browser. When a comment is submitted, the presence of this cookie is checked; if it's absent, the comment is flagged as spam. Additionally, the plugin assesses the time taken by users to submit their comments, helping to identify unusually fast submissions typical of automated bots.

The plugin also offers advanced users the option to implement specific rules in their .htaccess file to block spam attempts before they reach the WordPress environment. By adding customized rewrite conditions, users can effectively prevent unwanted comments or signups based on cookie validation. This functionality is particularly useful for those managing WordPress MU, as it allows for similar spam protection during user registrations.