Does showing a large subest of the pages that point to it, default ordered by something that's roughly equivalent to pagerank, with the ability to then search within those results capture the essence of what you're getting at?
No, not really. What I'd really like is to input the URL and get a search result listing that includes number of posts and date of last post at least.
There's actually a Firefox extension called AddaTweet that shows all Twitter conversations for any given link. Not everything, but someone's thinking about your problem. It's by Dmitry Shapiro (Veoh).
That sounds like it could work real well with a google finance type interface. A line graph showing a timeline of how much buzz the URL got, with links to the sampled data.