According to the post titled Perspectives about the news from people in the news from the Google News Official Blog, Google News will be allowing reader comments on their stories starting this week.
Comments are restricted to people who are "directly involved with the news," (Deep Jive Interests: Google News To Change Online News As We Know It. Here's Why) but it will certainly be interesting to see how "by adding this feature, [Google News] can help enhance the news experience for readers, testing the hypothesis that... a personal view can sometimes add a whole new dimension to the story." (Google News Blog)
Collaboration activities on the Google domain is not new (see Google Docs Redesign on my blog), but social media applied to news story is definitely an ingenious idea.
Next step: Google Search + Comments would definitely make for some interesting product!