It depends on how many other sites are also using the text copied from another site. There is a good chance your rankings will soar and you will get more traffic. And there is also a good chance that since your copy of the content is at best the SECOND copy that the search engines will fine, that your site will not rank or get much traffic and just do poorly no matter how much you optimize and promote it. After all, you are a thief and a criminal, aren't you?

But there is also a good chance that your site does well that it will be shut down for copyright violations after the owner of the content finds out and reports you. Going to jail is also another possibility, but that doesn't happen too often...! :-)