connections
If you have Java on your system, you can plug websites into Touchgraph and then see a graphical representation of who they link to and who links to them (made from google data). I added in some blog index sites and when you are using it you can see how while they don’t link directly to each other, they often link to the same sites. To get a closer look, click on the image above or just go to Touchgraph and have a look around.