fulford

Their contracts with the carriers allow for remote pings of the GPS chip (if there is GPS on the handset). Otherwise it's just cell tower triangulation.

It is 100% opt-in, but there is no "app" needed on the actual phone - so you're totally right if by "per app" you mean "per developer" or "per use case." So I might allow one company to locate my phone for a family-finder scenario, and another company to locate my phone for local weather alerts, for example. No app required in either case. Hope this helps.

Exactly - 250M potential users is what they mean. Right now they probably have very few consumer opt-ins.

Yes, it's 100% opt in.