What's Your Definition of Fair Use?

I may have been a little lax about copyrights back when I was in high school. Sure, we all knew not to plagarize, but that was about as far as copyright education went. Reading and hearing about the Napster lawsuits opened my eyes though, and I have to say, that's all it took for me to see copyrights as something that also protected artists' (and authors') paychecks.

However, I read this article on the measures one newspaper is taking to protect it's copyrights, and I cringed. Sure, these people who are sued for infringement can defend themselves by claiming Fair Use, but I really dislike companies using lawyers like battle axes.

So, if you read the linked article, tell me what you think: Were the lawsuits fair? And also, what, in your mind, constitutes Fair Use, as it relates to books, the internet, music, movies, etc?