I’m still not convinced that creating a new “+1” release every time a new song is added is the best way to represent this. The release group seems a bit confusing now, too.
From Bandcamp’s perspective, this is one album that the artist released on 2009-03-29 and then modified periodically (which is something that MB doesn’t have any way of representing). There’s only one URL, and if you buy the album (or just get it for free, since it’s “name your price” with no minimum), you’ll have access to all future songs.
The text on https://pocketful.bandcamp.com/album/pocketful-evergreens-a-collection-of-demo-recordings suggests that the artist may view each song as a single:
This is a series of unofficial releases.
But I think I personally would’ve just entered this as one release with an annotation describing when each song was added.
Edit: Maybe a series would be appropriate here.
This feels related to other unresolved issues with online releases, like how to represent the countries where a release is currently streamable. Physical media is fixed at the moment of release; if it changes (which is much harder to do!), it’s a new release. Online releases don’t work like that, and creating a new release whenever there’s a change (or one for each streaming site, which thankfully isn’t done often) creates data that seems to me like it’ll ultimately be hard to use and maintain.
For another example of a change to an existing online release, see Release “gingerbread” by beek - MusicBrainz. Track 7 is now named “martian prawn paradise” at https://b-e-e-k.bandcamp.com/album/gingerbread. In the Wayback Machine, I can see that the artist renamed it sometime between 2016-09-22 and 2019-08-18. MB still uses the old track name. Should the release be updated to use the new name instead? Should a new release be created? What about if an artist just corrects a minor typo in a tracklist? (I see minor differences in tracklists and artist credits all the time across different online platforms.)
Creating a new release every time that a change is made to an online album is certainly one way to record when the change occurred, but I’m not sure that it makes sense to consumers of MB data or will be manageable in the long term.