The United States adopted the Berne copyright convention on April 1, 1989. This means that original works are automatically copyrighted as soon as they are put down in tangible form (written on a restaurant napkin, typed into a notepad document, doodled on a post-it note) and anyone using that work for their own use (whether they are paid for it or not!) are in violation and punishable by law. The amount of damages the violator can be sued for is sometimes higher if the copyright
is registered, but not seeing the copyright notice on an author's work DOES NOT MEAN IT IS NOT COPYRIGHTED.The purpose of a copyright is to protect an author's right to the commercial benefits of their work, and the right to control how their work is used. When someone copies an article from a web page and puts it on their own, they are taking control away from the author. If they are reviewing the author's article, and use bits of it in their own work, that is considered 'fair use' and is not punishable. Fair use judgements mainly rely on the purpose of the use.
So, anyone who writes an article and posts it here is automatically copyrighted. Anyone who critiques that work is also copyrighted. In regard to stories, anyone who uses someone else's characters in their own story without specific permission from the author is violating copyright laws. (Fan fiction writers who don't ask the author's permission are in violation of copyright laws, but many authors allow it and don't prosecute. They have the right to prosecute, however, so anyone writing an article and posting it here that includes, for example, Princess Lea, COULD be prosecuted by the original author. Myself, I wouldn't want George Lucas breathing down MY neck!)