All these sites share the same directory and this same directory has been distributed on many sites even on Google owns sites.
Question: How come Google allows this practice and in their Webmaster Guideline explains that you should not
Google in their webmaster guidelines say, “Don't create multiple pages, subdomains, or domains with substantially duplicate content.�
http://www.google.org/Top/World/
http://www.google.net/Top/World/
www.dmoz.org
More From Philipp
# directory.google.com/ Top/Arts/Literature/Electronic_Text_Archives/
# directory.google.net/Top/Arts/…
# www.google.net/Top/Arts/…
# www.google.net/alpha/Top/Arts/…
# www.google.org/alpha/Top/Arts/…
# www.google.biz/alpha/Top/Arts/…
