The community can contribute to the database and use Musicbrainz tools like Picard to clean up the metadata in their music library.
Add yourself here… (see this for more details)
Musicbrainz describes itself:
"In 2000, Gracenote took over the free CDDB project and commercialized it, essentially charging users for accessing the very data they themselves contributed. In response, Robert Kaye founded MusicBrainz. The project has since grown rapidly from a one-man operation to an international community of enthusiasts that appreciates both music and music metadata. Along the way, the scope of the project has expanded from its origins as a mere CDDB replacement to the true music encyclopedia MusicBrainz is today.
As an encyclopedia and as a community, MusicBrainz exists only to collect as much information about music as we can. We do not discriminate or prefer one "type" of music over another, and we try to collect information about as many different types of music as possible. Whether it is published or unpublished, popular or fringe, western or non-western, human or non-human — we want it all in MusicBrainz."