1 Who is Source http://www.whois.sc/internet-statistics/
2 What is a portal anyway? http://www.acs.utah.edu/acs/news/portalsl
3 Whatis.com http://whatis.com
4 What is a portal anyway? http://www.acs.utah.edu/acs/news/portalsl
5 Whatis.com http://whatis.com