"South Koreans are
using smartphone apps to avoid the novel coronavirus":
Recently developed apps using public government data
allow users to see how close they are to where a confirmed Covid-19
patient has been. They can also see the date a patient was confirmed
with the disease, demographic data about the patient, and, crucially,
some of their location history.
At least one app,
called Corona 100m, will also alert a user if they come within 100 m
(328 ft) of a location visited by someone who’s had Covid-19.
Developers of such offerings have seen a surge in downloads...