Today is 'IPv6 Launch Day'. It differs from last year because now all participants are asked to keep IPv6 support turned on from now on! Whether you're an ISP or device manufacturer - you're asked to make it a default item.
ISNIC (and therefore the .is domain as well) has been IPv6 capable for some time, and all our operations are accessible through IPv6. Some thoughts from ISNIC's System Admin can be found here.