WhatsSpy Public is a proof-of-concept tool that allows an attacker to track every move of any WhatsApp user, even if the user has locked down their WhatsApp privacy settings. It requires a secondary WhatsApp account, a jailbroken iPhone or a rooted Android or PHP knowledge, Nginx or Apache with PHP, Postgres and a server. The app can also cross analyze the timelines of two users, such as Alice and Bob, to see who’s online or offline status. WhatsApp claims to have half a billion monthly active members who send “700 million photos and 100 million videos every single day””]