For those unfamiliar with Chilling Effects, it is a site dedicated to watching the DMCA and other mechanisms that may cool the free exchange of ideas.
The DMCA has provisions that prevent copying of copyright materials as does the current copyright law. However, it goes further and makes illegal almost anything that can be used to provide information that might lead to copying. As such, Google gets requests on a regular basis to remove entries from its search engines that would allow people to find out about copying techniques or to locate illegal copies of copyrighted material.
These "offending sites" may contain anything from exact copies of copyrighted work to information on how to circumvent software security to articles on techniques for reverse engineering.
Whereas there is certainly a financial interest on behalf of the copyright owners and there is an economic interest on behalf of legal licensees to see that others don't get for free what they have paid for, it is hard not to question whether the DMCA's wide provisions may stifle free exchange of ideas.