It's pretty neat. It's something that would be cool for the free wireless and free wardriving maps folks should be willing to put some friendly free competition up with them (update, it looks like someone has, called HereCast). And/or for them to provide a free Web API and a low cost access licence. I would certainly pay ten bucks a year to such a service.
Of course, I would also like it for the IEEE 802 comittee to add localizer data to the 802 meta and control standards, and also for all IP devices to start making their localization data available, maybe via DNS LOC and via SNMP, or both.