Comment by EvanAnderson

> Example of inherent client-side limitation would be how Youtube works: > ...

I thought about this problem a long time ago but never did anything substantive with it. I guess I'll articulate it here, off-the-cuff:

People used to post a "blogroll" (and sometimes an OPML file) to their personal blogs describing feeds they followed. That was one way to do decentralized recommendations, albeit manually since there was no well-known URL convention for publishing OPML files. If there was a well-known URL convention for publishing OPML files a client could build a recommendation graph. That would be neat but would only provide feed-level recommendation. Article-level recommendation would be cooler.

One of the various federated/decentralized/whatever-Bluesky-is "modern" re-implementations of Twitter/NNTP could be used to drive article-level recommendations. I could see my feed reader emitting machine-readable recommendation messages based on ratings I give while browsing articles. I would consume these recommendations from others, and then could have lots of fun weighting recommendations based on social graph, algorithmic summary of the article body, etc.