I really wanted to like Newsvine and I visited semi-regularly for quite some time. But I found that it didn't do much for me as I found other news sites more convenient and relevant to peruse. Their new version seems like a good step in what they want to accomplish, though.
One thing I've noticed by looking through the server logs for my blog: There is a huge bubble in news aggregators.
And really, it's not the news but the communities that form around it which really drive the traffic.