This number probably comes from NetCraft Web Server Survey: http://news.netcraft.com/archives/2011/10/06/october-2011-web-server-survey.html http://news.netcra

This number probably comes from NetCraft Web Server Survey: http://news.netcraft.com/archives/2011/10/06/october-2011-web-server-survey.html http://news.netcraft.com/archives/2011/10/06/october-2011-we... It indeed shows 43M "hostnames" as of Oct 2011.