TouchGraph Google Browser (also available for Amazon.com and Facebook) shows connections between websites listed in Google's database. You can graph connections based on URLs or keywords. Here's part of the graph I got when I put in "instructional technology" with the quotation marks. I focused on the section with CU-Denver bcause that's where I'm taking an instructional technology class.
I read about it on TechCrunch.
Also posted at Issues and Trends in IDT.