Digital Sliderule for Determining Copyright/Public Domain Context

http://librarycopyright.net/digitalslider/

This digital slide is a neat tool, licensed under a creative commons license, for determining whether or not something is copyrighted and thus in need of either a fair use determination or the seeking of permissions. (If in the public domain you can freely use).

The slide rule was discussed in a recent arstechnica article:
http://arstechnica.com/news.ars/post/20080718-copyright-so-complex-heres-a-slide-rule-to-decode-it.html