The phrase describes a type of online service designed to transform video content from a well-known video-sharing platform into audio files in the MP3 format without cost to the user. For example, an individual may use such a tool to extract the audio track from a music video or a lecture available on the video-sharing site, saving it as an MP3 for offline listening.
These services gained popularity due to their accessibility and convenience, providing a means to enjoy audio content from video sources on devices that may not readily support video playback, or where bandwidth constraints are a factor. Historically, the rise of digital audio players and the desire for personalized audio collections spurred the demand for such conversion tools.