"Near-instantaneous porn downloads will soon be possible in Japan thanks to a speedy new, widely available, fiber-optic service from ISP KDDI. The service will offer upload and download speeds (each way) of up to one gigabit per second. The service goes online October 1 for single family homes and low-rise apartment buildings for about $56 a month, and will be considerably higher than the current 100 megabits per second norm most Japanese citizens already enjoy today. If the outcome of the 2008 election doesn't get me to move to another country, these currently untouchable download speeds just might."
Intertubes: 1Gbps Fiber-Optic Service Arrives in Japan on October 1
I do not think this figure will be anywhere near the effective speed... people commonly confuse available bandwidth with actual rate of transfer, just because your smallest capillaries have become 10x as big does not mean you will have the blood to pump into them. Only the larger companies are even using 10Gbps distribution in the datacenter, there is pretty much no way 1Gbps could be maintained at last-mile, especially not for such a densely populated country like Japan.
Basically, it's neat that they have the infrastructure, but pretty useless. Yes, data transport is booming with the widespread adoption of optical media, but until we come up with something to match it in terms of integrated circuitry, processing, and storage, a lot of that capacity will be collecting dust.