Exploring the paths of Wikipedia with Pathway
Pathway is an OS X desktop client for the Wikipedia, the free encyclopedia. It keeps track of relations between pages you read using a handy network map, and makes them searchable via Spotlight. It is also able to save the researched network of pages for later use.
Via TUAW.
On a related note: While there are all these applications available make the Mac OS X platform cool, I would still wish Apple would become a more responsible company by producing greener products.