A modern reinvention of Trackback-style features could connect conversations on different websites in the same way that @ replies work on Twitter.
The lost infrastructure of social media.
Anil Dash

Given that the noindex and nofollow attributes can remove most of the incentive for the spam links, JS can hide the list of responses by default (so the clickthrough incentive is diminished as well), and spam detection is way more reliable now, this is absolutely doable.