MusicBrainz Rating System
Rating is a new feature which is currently being develloped (Oct 2008), and which should be integrated in the 2008 server release.
Users will be able to rates MusicBrainz entities (artists, labels, releases and tracks).
Each user rating will be a number between 0 and 5. Then the system will aggregate users ratings to compute the average community rating.
By default community rating is shown. As soon as user rates an entity, he/she will only see its own rating.