I don't have a particular opinion on this, except that inline comments that are publicly visible must be able to be moderated by the community, and that smaller communities in particular should be able to opt out of this extension. They sound like a great idea, but we're much more likely to get comments like "this isn't true" or "this [highly unreliable website] disagrees", and that just creates problems for readers. We can assume good faith until the cows come home, but we should also be realistic and realize that those comments are going to make our articles look more like Twitter and Facebook; that is, they'll be opportunities for disinformation.
Risker/Anne