I don't mean to be a huge jerk - I think the service is cool - but IPv4 exhaustion is months away! All of the major GeoIP vendors have IPv6 support. It's simultaneously saddening and frustrating that it might as well not exist.
Now, people /have/ been predicting some crazy run on IPv4 for some time now, I was pretty certain it was going to happen in 2011 and while a run is still quite possible, it hasn't happened yet, and there are a bunch of outstanding /8s that could very well be returned; the DoD has been returning blocks, and they still have a bunch more they could return. Based on my own previous expectation that runout was going to occur in 2011, I'd be surprised if we run out before 2015.
Now, if you are dealing with network admins and infrastructure types? IPv6 is very important. I give my customers an IPv6 address by default, and will give a /64 upon request. It's pretty important for the sort of people I have as customers.
You see, we're the ones who have to deal with this 'nat hell' - and make no mistake about it, it will be hellish.
However, from a business perspective? If you are going after business types? The internet is still entirely IPv4.