Interest search engine

This search engine is great for when you aren't looking for a specific answer, but just for more information relevant to an interest:

Clusty.com

The results are in two panes. The right-pane lists links in the classic ordered fashion, very Googlish. But in the left-pane is a small tree of browsable clusters of results, the clustering being pseudo-topical.

I tried "Piaget's epistemology", and the clusters were immediately interesting and required no scrolling or page-nexting. I like it.

The only drawback? Seems to take a few seconds longer than Google to return results.