I put together this graphic in order to illustrate the decline in connectivity among top-25 teams from 20 years ago to today. Here's a brief write-up:
http://bcftoys.blogspot.com/2010/03/connectivity-in-college-football1989-vs.html

I also posted on this topic about a month ago:
http://www.bluegraysky.com/forum/index.php?mode=entry&id=15905