[note to admin: sorry for the duplicate thread with the simpler title]
The exhaustion of the ipv4 address space is imminent and this time around, there do not seem to be any hacks remaining to get around that fact and yet everyone seems to have their heads buried in the sand regarding the issue, the most guilty parties, imo, being the ISPs who have been extremely complacent about rolling this out for their end users.
If I understand correctly, there are several disincentives against going ipv6, one of the most important being that it is NOT backwards compatible with ipv4 (
http://cr.yp.to/djbdns/ipv6mess.html ). Practically speaking, a site that is being served on ipv6 only is NOT ON THE INTERNET AT ALL - being inaccessible to 99.9999% (or something like that) of the internet population!
Until ISPs give ipv6 connectivity to the end-users of the world, the limited pool of ipv4 addresses is going to become more and more expensive over time as it would be ludicrous to put a host on ipv6.
A black market in ipv4 addresses seems to be inevitable, but perhaps by spurring quicker ipv6 adoption, the increased costs and inconveniences of such a transition era can be made as short as possible. Plus, I think everyone hates opportunistic b@st@rds (unless we're in on their racket that is

) and we want them to make as little money as possible engaging in black-market trading of ipv4 addresses.
One possible proposal would be for sites like freebsd.org and kernel.org which are frequented by network-knowledgeable people to have an
"ipv6 only hour" deliberately inconveniencing people who do not have ipv6 connectivity. System administrators working in ISPs and/or directly affected by their services will be the ones which would be most inconvenienced by such. Encouraging these network-savvy people to demand (or at least familiarize themselves with) ipv6 is what's needed to reach the tipping point for ipv6 adoption because these are the people who are directly involved in crafting policies for ipv6 rollout.
To lessen controversy and to provide fair warning, a site like FreeBSD.org could say that they will go ipv6-only for 1 hour every week for the first 3 months, adding an additional hour of ipv6-only time every couple of months thereafter.