Let me start with some background info:
WiFi has a signal range (radius) of about 300 feet (outdoors)
If I detect your WiFi you could be anywhere in that 100,000 sqft large area.
Bluetooth has a signal range of 30 feet (outdoors).
So placing your BT in to the Discovery mode and if I can detect your Bluetooth you must be very close :)
Using both signals one can set your location more accurate.
Background: Abstract —Crowd-sourced Wi-Fi-based localization systems uti- lize
user input for RF scene analysis and map construction. Such systems
reduce the deployment cost and privacy concerns that expert-based site
survey systems can create. However, t he main bottleneck of such
crowd-sourcing localization systems is a bootstrapping stage, where
lack of contributions by users result s in no accuracy guarantee and
frequent unnecessary prompting for users’ input, even for explored
areas. In this paper, we prop ose a crowd-sourcing localization system
that uses both Wi-Fi scene analysis and Bluetooth beacons to address
the insufficient con- tribution challenge. After prompting for user
input, the mobile device not only submits Wi-Fi fingerprint to a map
server, but also enables Bluetooth beacons to disseminate/share its
location and fingerprint information to quickly populate the signal
map. Then, subsequent user devices entering the area can discover the
Bluetooth beacons and are able to instantly obtain room-level location
information without causing unnecessary prompting to users. We
implement our proposed system in the Linux OS and evaluate the
prototype extensively through both experiments and simulation.
Our evaluation results show that using Bluetooth beacons help to
improve signal map growth, while maintaining reasonable localization
Apple subtly introduced iBeacon as part of iOS 7 at WWDC 2013, though it mentioned the feature only in a single keynote slide and didn't go into detail at all. But this hasn't stopped companies from taking advantage and launching products and services that make use of iBeacon.
iBeacon essentially makes way for new range of apps and functions. With it, stores can pipe coupons to your phone, mapping apps can offer indoor navigation and more. Here's the real clincher: iBeacon might just be that nail in the coffin for NFC.
So finally to answer your question, once upon a time one could go completely anonymous in to the mall and just browse around. Now days everyone will know you are in the mall, more, they will know what store you went in to. How about that for location accuracy.