Contents which are double or even several times on the same or other URLs, is called duplicated content. All this is about copied texts. If the search engine detect such duplicates, the pages will be valued negatively or simply as spam. It can also happen that both pages will be deleted from the index, because in most cases the original is not differentiable from the copy. The search engine can’t guess which one copied from the other one, so both will be deleted. Usually, this leads to complaints from the owner of the original sites. For the avoidance of half-cocked action, search engines like Google are only getting active when several passages are identical. www has a copyright and the violation of it is still a big problem.