The power of metadata, by Rael Dornfest and Dan Brickley, 2001:
While MP3 CD rippers currently embed lots of descriptive information (track listings) right into the encoding, they omit the most crucial piece of data from a fan's point of view: the CD and track identifiers. The simple unique identifier for a song on a CD, while only a tiny fragment of data, could allow both peer-to-peer and web applications to hook into a marketplace of descriptive services. How could MP3 services use this information?
iTunes stores disc IDs in the ID3 tag when it rips CDs:
If you have some MP3s in your iTunes library that are without all the track information (say, it just says Track 01, instead of the song name) then highlighting the tracks, and hitting Advanced/Get CD Track Names actually works, even if you don't have the CD at the time.
The MusicBrainz Tagger analyses MP3s and generates a unique TRM track ID number: eg Sonic Youth's 'Cross the Breeze
MusicBrainz users can browse and search this catalog to examine what music bands have published and how artists relate to each other to discover new music. The music metadata and its ability to uniquely identify music will also enable non-ambiguous communication about music.
Audioscrobbler collects information about the music you listen to, and recommends similar users and artists based on that data:
Audioscrobbler endeavours to be your personal music advisor. It grows to know what music you like by monitoring what songs you play on your computer. From this information you can discover other users that share some or all of your taste in music. You can also view data showing what your most-played artists are, and find out who likes a particular artist the most. Audioscrobbler is a fantastic way of discovering new music, and discovering people who like the same music as you.
Emusic is a subscription service that allows you to download unrestricted MP3s for £10 a month.
There are open networks that allow you to download a much wider range of higher quality unrestricted MP3s for free.
There is no centralised or decentralised subscription service that has the permission of all the record labels to provide high quality MP3 recordings, along with a web-based interface that uses unique track and album IDs to allow commission-earning linking from external sources. But there should be.