A new startup company, TenGrade, uses a different approach, explicitly asking people to give their opinion on where something (anything in the universe) ranks on a 0 to 10 scale. They make this fun and easy using a mobile app, and then let you compare your rankings with various slices of whatever community you care about, and how they change over time.
It is a very interesting approach. To paraphrase Yogi Berra, you can learn a lot from listening to people. As I write this, Pizza is a 7.9, where as Grapefruit is a 6.8. Barack Obama is a 6.0, which puts him ahead of disgraced baseball player Alex Rodriguez (Arod) at 1.0.
Their rankings have the advantage of clear numerical interpretability, although I think they will eventually discover the need to normalize individual rankings: a 7.0 given by a sourpuss means something different than a 7.0 granted by some easy mark. It will be fascinating to see what kinds of things people will feel driven to state an opinion on. As an academic, I would love to experiment with their data and see what we could do with it.
TenGrade may face a bit of a chicken-and-egg problem: the rewards from ranking something come from seeing what others say, but until they achieve critical mass there may not be enough content their to make it compelling. Why will people bother to give their opinions ranking everything in the universe? I don't know: but frankly I didn't know why anyone would tweet, post on Facebook or enter Amazon reviews or complaints on TripAdvisor, either.