Since the early days of CritiqueBrainz people were asking to be able to put a rating on their reviews. You can just write a number in the text, but that's not going to be used anywhere in the UI. Original proposal (https://tickets.metabrainz.org/browse/CB-4) was to integrate CB with the 5-star rating system that we already have in MusicBrainz.
After multiple attempts to do this integration we couldn't find a good solution to the synchronisation problem. You could make a review for release group and put a rating on it, which will be sent to MusicBrainz for storage. There is, however, no good way to know if you change that rating later in MusicBrainz to sync these changes with CB. Another issue is that you might not want to change the rating that is associated with your review at all, since text of a review and a rating that you put with it are inseparable from each other.
Later we started considering moving the rating system entirely to CritiqueBrainz, since it seems like the right place for this kind of data. This would also be convenient in cases where entities for reviews come from a place other than MusicBrainz, like BookBrainz for book reviews. There are two problems with completely moving the ratings to CB:
- Not all entities that are currently rateable in MusicBrainz can be reviewed on CritiqueBrainz, so there's no way to associate a review with them.
- This migration would most likely take a significant amount of time.
It would still be nice to have a way to put a simple 5-start rating on reviews without having to do all the difficult migration work. This would be a first step, but still very useful.
The main ticket for the rating system is CB-244. The description I provided above should give you an overview of what our idea is. There's a bit more information in that ticket and ones that are linked to it.
We'd like to hear what you think about having ratings in CritiqueBrainz. Feel free to share you ideas, suggestions, concerns. You can comment on this topic or in JIRA.