25 Feb 11
07 Jul 11 1:14 pm
If your article is posted by another website as point of reference with a link pointing back to your website, then Google looks at that positively. Like in your example, if you just copy and paste the information on Elvis from Wikipedia and publish that as your own, then you get penalized for that. If you write your own article and quote parts of the Wikipedia article on Elvis or reference a paragraph or two of it on your post, then your article and the of Wikipedia's is viewed by Google in a favorable light.
Hope that helps. Have a good day!