I also desperately want something like this to succeed. I want to be able to see others' reactions on all NYTimes articles, for example, not just the handful each day they enable comments on, or the occasional one submitted to HN. And I want it to have all of the standard functionality -- hierarchical comments (like HN and Reddit), upvoting and downvoting, auto-collapsing tangential threads with less votes (like Redd…
Which could be helped by storing the page source or something (which still has a ton of issues associated with it) but then you have a problem of discovery, and how do users tell the pages apart with the same URL? Simple version numbers?
Another problem is you might have 2 URLs that are basically the same page, but with some query parameters that subtlety distinguish them - they are different URLs though. Should there really be two discussion sections for a page that's only differentiated by a referral link or a stylistic preference? Probably not, but there is not an objective metric here we can use to make the call.
What if we use just the base path, e.g. facebook.com? It could be useful for small sides but for large sides you'll run into issues with scoping topics.
it's a really hard problem IMO