I've been following Peer Index for a month or so. Peer Index is attempting to "help you discover the authorities and opinion formers on a given topic."
The idea is to use the world of social media (blogs, twitter, facebook, linkedin, etc) to determine who are the "authorities and opinion formers" on the web.
I like the idea. The execution is the hard part. When I first tried it out about a month ago, I thought the service was too thin. Too few topics and too few "authorities" in each topic.
Sometime in the past week or so, they added a bunch of new topics and a lot more authorities in each topic. And they've added a bunch of new ways to navigate the service. I like where they are headed with this.
In a perfect world, you could enter literally any topic, like "sushi in london" and find out who the experts are. Then you could follow them, read their opinions on the topic, and possibly even contact them.
In order to reach that perfect world, I think they are going to need to open this up. Let the "crowd" source the topics and the authorities and then use their algorithms and systems to maintain the topics and rankings. At least that is my gut on how this would work best.
In any case, this one is worth watching.