Victor, If I’m understanding your last portion properly, there’s already Reddit-like aggregation hubs like IndieWeb News and that allow you to cross-post to them using the idea of Webmention.

It would definitely be awesome to see other incarnations of these sorts of discovery related platforms. Pre-print servers could certainly work like this and allow people to post their research on their own websites and syndicate copies to hubs where others could discover and read it as well as comment back onto the original. They could also serve as archives of work if/when the original might disappear from the web to improve longevity.