A high speed multidimensional query seems like it would be useful for visualizing and analyzing server logs to look for attacks and other trends.
The version with online demos uses latitude/longitude for the spatial dimension, but a new version we're working on (under the master branch on github) allows arbitrary x,y addresses. With that, we've encoded IP addresses as locations in space-filling curves to play around with source IP/destination IP datasets. It's particularly nice because the hierarchical nature of the spatial addresses end up mapping to larger and larger subnets of the IPv4 space.