EyePlorer

I find this tool fascinating and potentially useful to certain people.  The division of the topic is the most useful part, I think.  It's just the way I teach students to come up with keywords:  place, people, time period, society, discipline, etc.  I find that following the links is a bit disappointing--I'm not getting more than a quick factlette on each subtopic, but that may be the point.  For narrowing down a broad research topic, it's great.