The copyright law is when someone writes something and you try to use it is safe by the copyright law so if you use their words or pictures they can take you to court.
Things that are protected by copyright is books, music, drama works, motion pics, and sound recording.Ect.
Things that are NOT protected by copyright is titles, names, slogans, and ideas.Ect.
A public domain is works that can be used without permission.
BUT you still need to give the source. Here is a link that you can go to, to find what is copyright and public domian and plagiarism. http://www.cyberbee.com/cb_copyright.swf
So if you see anybody else's work on the internet and you would like to use it, just put it in your own words so it won't be copyright.That way you won't get in trouble!!!!!!!!!!!!