Since its advent the Internet has been making its way into very farfetched corners of the world, allowing people to virtually reduce distances. Now the Internet was based on a notion called IP (Internet Protocol), Internet Protocol Version 4 (IPv4) to be exact. Now as the number of computer connected to the Internet grows, the amount of numbers in the IPv4 protocol was finite. Simply put, there are 2^32 useful addresses in IPv4 (subtracting the loopback and the non-routable). With all the connected computers (and growing) this number looks very small. That being said the number of non-allocated IPs is decreasing at a very fast pace. To cater to this problem IPv6 is brought forward. Although there are a lot of problems with the implementation, it certainly brings forward a huge pool of addresses supplemented by some really good security benefits. Some of them include decreased vulnerability to the man in the middle attacks and larger atmosphere surface area, making worm proliferation less effectual. While some may consider these benefits to be negligible, they should be embraced within a set economic cost.
That being said, there is a multitude of problems while migrating from IPv4 to IPv6. Some might even consider a problem of unprecedented magnitude as the migration can and will affect anything that touches the World Wide Web. It is not just that there are technical aspects of the Internet that will be effected, but there are certain other aspects that need to be regarded while carrying out the migration.
First and foremost is the economic impact of the migration. It is not necessary that all the allocated IPv4 spaces are being used for something. With the latent addresses in their hold many ISPs will display an increase in their costs (for the apparent value may seem higher and the lack of available spaces). This could result in the rise of the barons who will hoard and then resell the IP spaces in the virtual world. To cater to this laws could be formulated to penalize all and any hoarder for squatting on unused IPs. This could be a silver lining for the ones who failed to migrate to IPv6 for whatever reason.
Then there will be the short term issues...