Yikes. (Is this actually based on knowledge of where I am at the moment based on GPS?)
@harrymccracken I'm pretty sure its not done via the mobile internet but directly on the cell network level.
Also I guess this could be broadcast only from certain towers and only to the phones booked in to that tower.
The result is that it can be very highly localized without needind to know any geopositions.
@harrymccracken I always have to click through for details