I'm building a rss client with an extra layer to have user comments/threads. This lets you create your own feed of articles entirely but with a social aspect.

I want it open source and free, just building an app that I'd like to use myself.

I built the exact same thing 2 years ago, and then figured out that Inoreader actually already had it in their product. They are disabled by default, probably because this feature is not popular at all.

I've dreamed of something like this with a geographical bounding (hard part) for what comments/requests you encounter.