I have a Google Blog Search Alert looking for posts over IPv6 in my RSS reader. What strikes me is the number of posts explaining how to disable IPv6 in Windows Vista, MacOSX, Ubuntu and other flavours of Linux.
It looks like disabling IPv6 makes web browsing faster for a lot of people, independently of which operating system is being used. One guy even wrote in one of his posts “In order to fix this problem” . IPv6 was supposed to be a solution, not a problem.
I can think of several rational explanations for the poor user experience. If the DNS query for a web site first returns a AAAA record and you do not have IPv6 running smoothly, the browser will first time out before trying the IPv4 address. If the IPv6 tunnel broker, gateway, etc is overloaded, you are up for a painful experience, too.
However, it is worrying that people need to disable IPv6 on their computers. If and when there will be IPv6-only web sites, they will not be able to access them.