I’ve had an idea, that I could easily pivot to this and become a FOSS solution. But, I wonder if it actually solves a problem. Essentially, I wanted my lemmy instance to allow sign-ups. But, the posts and channels were auto-generated. So when you log into the app or sign-up it creates a community in the instance along with it. (loom.nyc/c/pexavc) and then all the posts are automatically generated from the posts you save anywhere in the fediverse. (The app supports lemmy and mastodon for now). But, this would also allow all your bookmarks to essentially “federate”.
Edit: Tbh, it sounds like a more “silent” cross-posting
Ah yes! I almost do that already. With RSS as well. So you can combine communities and RSS Feeds, not mastodon users yet though. It’s kind of fun standardizing all the different ActivityPub implementations into a single data model. Mastodon timelines or users are essentially whole communities.
To be honest, building a web-version of that pipeline as a NPM package might be helpful for others, piping in all the different types of fediverse content into a single stream.