Ratings suck for differentiating items on a website. "5 stars" and "1 star" have some meaning, but everything else is worthless. For this and a few other good reasons, Flickr just collapses ratings into "favorites".
Flickr has an algorithm called "interestingness" which tries to guess which photos are worthwhile by looking at social activity and other such metrics. However, I agree that it isn't nearly good enough, if you are a real lover of photography. Flickr Explore tends to be filled with cliche photographic beauty. That said, if you expect a machine to tell you what good art is, you're going to wait a long time.
Flickr has an algorithm called "interestingness" which tries to guess which photos are worthwhile by looking at social activity and other such metrics. However, I agree that it isn't nearly good enough, if you are a real lover of photography. Flickr Explore tends to be filled with cliche photographic beauty. That said, if you expect a machine to tell you what good art is, you're going to wait a long time.