Left Coaster includes the following disclaimer at the bottom of a post about Education Secretary calling the NEA a "terrorist group":

FAIR USE NOTICE

This article contains copyrighted material, the use of which has not always been specifically authorized by the copyright owner. I am making such material available in my efforts to advance understanding of democracy, economic, environmental, human rights, political, scientific, and social justice issues, among others. I believe this constitutes a 'fair use' of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material in this article is distributed without profit for research and educational purposes.

The post contains excerpts from a copyrighted Associated Press article.

Has a blogger been accused of copyright infringement? It's only a matter of time, and I'll admit to some trepidation about using photos (or editorial cartoons) from news sites -- even if it's for subsequent commentary.

...some thoughts about the issue here, including a step-by-step walkthrough of Section 107 from a blogger's perspective.

...Wired has a similar article that might be useful.