Sluggo has limited time under these circumstances, so all I am going to do is post a link (unearthed by waning_estrogen) to Chilling Effects Clearinghouse. This site is a . . . well, since it's all about posting stuff written created by people other than the one doing the posting, I'll just paste a couple of paragraphs copied from the site:
Do you know your online rights? Have you received a letter asking you to remove information from a Web site or to stop engaging in an activity? Are you concerned about liability for information that someone else posted to your online forum? If so, this site is for you.
Chilling Effects aims to help you understand the protections that the First Amendment and intellectual property laws give to your online activities. We are excited about the new opportunities the Internet offers individuals to express their views, parody politicians, celebrate their favorite movie stars, or criticize businesses. But we've noticed that not everyone feels the same way. Anecdotal evidence suggests that some individuals and corporations are using intellectual property and other laws to silence other online users. Chilling Effects encourages respect for intellectual property law, while frowning on its misuse to "chill" legitimate activity.
That about sums it up. Among their related resources is a letter written to Warner Brothers by Groucho Marx in response to the studio's demand that the Marx Brothers not use the title A Night in Casablanca for their new movie because it was too similar to the title of their movie of several years earlier, Casablanca. Not Groucho's best work, but amusing.