if a person writes some information in wikipedia and wikipedia has a no copying the info policy,what if the same person that wrote the info in wikipedia was also a member of another wiki site and wrote the same info there. would this breach copyright?
Your "what if" question doesn't reflect Wikipedia policy: All of the text in Wikipedia, and most of the images and other content, is covered by the GNU Free Documentation License (GFDL). Contributions remain the property of their creators, while the GFDL license ensures the content is freely distributable and reproducible. (See the copyright notice and the content disclaimer for more information.) from Wikipedia:About, http://en.wikipedia.org/wiki/Wikipedia:About#Trademarks_and_copyrights (emphasis added).