Song Identifier is a subscription-based multimedia extension for Firefox that specializes in identifying audio tracks from various online sources. This tool allows users to seamlessly identify songs playing in videos or audio streams, providing a countdown status bar for real-time tracking. While it works effectively on popular platforms like YouTube, users may find limitations on sites such as Soundcloud, where the media is served differently.

To enhance the experience, users are encouraged to create a personal account on acrcloud.com, which offers 100 free identifications daily. This ensures that the shared default account is not overloaded, preventing errors like '3003' from occurring. The extension requires permissions to access the active tab and storage for saving user settings, making it a straightforward and user-friendly tool for music enthusiasts.