I’ve been a little bit too synthetic here: sorry.
Given releases that are both in Discogs and Spotify/Apple/Deezer (so with a similar amount of information on the page), Discogs performs still better in terms of page ranking in search engine results.
Given releases that are on digital media only, Spotify/Apple/Deezer perform better in terms of ranking than others like Bandcamp, even if the second one has usually more information on the page than the three.
So it’s a matter of search engine optimization and potential issues I would verify for MB comparing it to Discogs/Spotify are:
- indexing: sitemap seems outdated;
- internal links: as discussed already in the new homepage proposal, the paths to reach the pages of the site are useful for users and search engine bots. The kind of links can range from simple alphabetical lists of artist, like in Jazz Archives, to rich categories of genres, like in Rate Your Music. In case of RYM, it performs better than MB even though it has less information about releases, with the list of recordings generally missing;
- grouping information on a single page instead of splitting in multiple places: in Discogs you have pictures, links to related artists/groups and listing of releases on the same page, but in MB such information are scattered across different pages (cover arts, relationships, …). It’s not a case that if you are looking for an album, in case you get a MB result, it’s more likely to get the cover page rather than the overview.
Hope it helps