if I publish a program without any legal copyright, there is nothing to stop Nexxon, Microsoft, Apple, Symantec or any other commercial "I pwn joo 4 $" organisation putting my code in their program and claiming ownership and even authorship of my code!!! And they would be in the legal right, and I would have stolen from them, in the eyes of the law, by giving away code I wrote, without copyrighting it to my self.

It is legal for them to take it off me, and call me a thief!

quoted from http://forum.ragezone.com/f425/idiots-guide-legal-infringements-764705/