For a while I've thought it would be nice to have a web page that takes a URL as input (via query parameter) and then displays all the discussions it can find for that URL. At a minimum, it could search Hacker News, Reddit and Twitter.
I would use this to add a "see discussions" link to the bottom of all my articles. It'd be handy too if the site exposed an RSS feed for all the comments; I'd hook it up to Blogtrottr to get batched notifications for new comments. Bonus points if the site gave me a single feed for comments on any of my articles.
Besides that, this could be complementary with Findka. As I explain on the landing page, Findka intentionally unbundles discovery from discussion. Discovery is the main goal. I wouldn't mind facilitating discussion, but I don't want to bake it into Findka. I'd rather keep the focus narrow.
So this service would be perfect: each essay you receive from Findka could have a "discuss" link that goes to this separate service. And since it's open-source, I could respond to all feature requests with "happy to accept a PR." You could even fork the code and self-host your own instance. I could add a setting to make the "discuss" link point to a custom URL, or you could just add a bookmarklet that goes to your discussions page for the current URL.
Perhaps I'd make a subreddit or a Discourse forum for Findka so users could discuss essays with each other. The discussion aggregator could have convenience links for posting to various places. There could be an additional query parameter to specify suggested discussion sites, so Findka users could see a "post this essay on the Findka subreddit" link.
A cursory Google search didn't turn up any existing projects that are like this. Tell me if you know of any. I'll probably start working on this during the weekend (with Biff of course!).