MP3Cattle is an MP3 manager/organizer and ID3v1 editor that uses MySQL on the backend and allows multiple users to input their rankings/genres on MP3s. Playlists can then be generated through queries on a single user or mutliple users' data.
Open source project that offer summary and download services on this page is a project that carry out their development work on other open source development sites. Their work is linked to this page via a feature called OFI, and their work is not carried out here on OSDN site.