Watchmarker for YouTube is a free Firefox extension designed to improve the way users track their video-watching habits. Unlike YouTube's built-in feature which only marks recently watched videos, this addon offers a comprehensive solution by keeping a complete history of all videos viewed. It allows users to manage their watch history more effectively, ensuring that no previously watched content is overlooked.

The extension also includes useful features like backup options through export and import functionalities, enabling users to archive their history and prevent data loss. Users are encouraged to manually sync their history for a more thorough record. Overall, Watchmarker for YouTube is a valuable tool for anyone looking to enhance their multimedia experience on the platform.