Scot Golder, who I've shared a couple of meals with at conferences, is investigating shared annotation of webpages, through his Webbed Footnotes project. I'm interested to see how the rating system works out. Unfortunately, I've got way too much work to seriously participate in someone else's research project, but maybe some of my 6 or so readers will join in. Besides, I don't read the NY Times, the target publication, online that much.
P.S. That's a joke son. I know there's more than 6 of you out there.