I've been having this exact same idea. Basically a way for any RSS reader to discover comments from anywhere. Of course you run into the problems of moderation

I've been having this exact same idea. Basically a way for any RSS reader to discover comments from anywhere. Of course you run into the problems of moderation and latency, but I believe some clever systems around prefetching and shared lists of verified and banned users could work. But the main problem I've run into for link discovery is the voting system. If you actually want a distributed system counting votes becomes expensive fast.