lammert - 8:39 pm on Jan 28, 2011 (gmt 0)
If you can ping an IPv6 address you are very lucky. Finding a data center which supports it is currently still a problem. Many large hosting companies haven't rolled out their IPv6 infrastructure yet. They have their own private unallocated pool of IPv4 addresses and may think that they will be able to supply their customers in the near future with IPv4 addresses, but the problem is that new end users won't be able to connect.
It is a sort of Y2K problem. Part of the buzz around it is hype and spinning to get the cash registers running. Different from the Y2K problem is that there is no fixed date that the Internet stops working. Actually the Internet won't stop working and all old connections will still function as before. It is that silently a second parallel Internet will emerge with only partially access to the old IPv4 world trough IPv6-IPv4 gateways and proxies.
One of the things which boggles me is how search engines like Google will handle that. Currently if an IPv6 client searches on Google, the SERPs are the same as with an IPv4 address. But if in the future an IPv6-only clients connects and Google would also show IPv4-only sites, the client would receive "Cannot connect" errors with these sites. That is not good for the user experience and one option could be that search engines would only provide IPv6 capable sites in the SERPs for IPv6 clients and hide the IPv4 sites from the listings.