There need to be more "find things like this" buttons in the world. I love Pandora for being able to find related works very quickly, but I hate the lack of re

There need to be more "find things like this" buttons in the world. I love Pandora for being able to find related works very quickly, but I hate the lack of real ability to explore. This seems to be a nice mix. Why don't more sites leverage the "if you liked X, you'll love Y" data that gets generated by millions of clicks?