The rules and regulations regarding copyright law and the Internet change periodically, as the Internet is still a fairly new medium, as well as an ever-changing one. Copyrighted works which may be available on the Internet include pictures, graphics, logos, news articles, novels, music, and much more. The large amount and variety of copyrighted material available on the Internet adds complexity to copyright law, and in many instances the applicable laws may not be clear. Generally, most works created prior to the 20th century are not copyrighted. Older works may be classified as existing in the "public domain," and therefore copyright laws do not apply. "Fair use" laws also often apply to copyrighted works on the Internet. Fair use allows for short excerpts of copyrighted work, with proper attribution. Fair use allows for commentary, parody, and reporting, and is important in guaranteeing creative freedom. Fair use does not allow others to plagiarize copyrighted work.