what happen if let say I write artcile on my web site and I have 20 unique article ( this article is not yet found by google search engine) someone stole my article and claim as his article? is that legal? what I can do in this situation
If you wrote the article and this person has published it on the web, you can try contacting the person about it. If he/she does not take the content off the server, you can contact his/her hosting provider and have them take the content off for you.
You article is most probably indexed by other search engines like MSN - you can proove you got it published first this way