The administrators of certain WiFi networks need to know exactly what kind of information is being sent over them. For such purpose, they can make use of tools of the likes of Shark for Root, capable of intercepting the traffic of all the devices connected to a wireless network.
Only for rooted devices
This app works on rooted devices and is based on Tcpdump, the command line tool the main function of which is to analyze the traffic sent over a network. It can intercept and read the data packets that are sent and received by the different connected devices.
We shouldn't have to remind you that this application should only be used in those cases in which, for security reasons, you need to intercept the data transferred over a network and after warning all its users. Otherwise, it could be understood as an important violation of the user's privacy as it could be used to steal login credentials and passwords for different services such as Facebook or even email providers.