For further information about the limitations of any of these rights, consult the copyright code or write to the Copyright Office. The copyright in the work of authorship immediately becomes the property of the author who created the work. Only the author or those deriving their rights through the author can rightfully claim copyright. Copyright is still violated whether you charged money or not, only damages are affected by that. Postings to the net are not granted to the public domain, and don't grant you any permission to do further copying except perhaps the sort of copying the poster might have expected in the ordinary flow of the net.
Fair use is a complex doctrine meant to allow certain valuable social purposes.
Ask yourself why you are republishing what you are posting and why you couldn't have just rewritten it in your own words. The ownership of names is also from trademark law, so don't say somebody has a name copyrighted. Fan fiction and other work derived from copyrighted works is a copyright violation. Copyright law is mostly civil law where the special rights of criminal defendants you hear so much about don't apply. Watch out, however, as new laws are moving copyright violation into the criminal realm.