Access logs may offer service providers a lot of information about specific users. Depending on the type of the service offers, the operator is capable of obtaining the user’s IP, location, communication habits, device information and so on. In this paper, we analyze a sample instant messenger service that is operating for a certain period of time. In our sandbox, we gathered enough data to correlate user communication habits with their localization, and even contacts. We show how seriously metadata may impact the user’s privacy and make some recommendations about mitigating the quantity of data collected in connection with this type of services.

The paper explains the force induced by the electrostatic field on the electron as a recoil force. The starting point is the hypothesis that in the dynamic equilibrium with the vacuum, the electron simultaneously absorbs and emitts energy. With no external electrostatic field the radiation patterns of absorption and emission are assumed to be isotropic. The external electrostatic field induces anisotropy of the emission resulting in a recoil force. The paper presents a theoretical description of this force using a model of the angular power density pattern of the emission in the form of an ellipsoid. Calculations show that the total radiated power is extremely high. This radiation is compared with the electromagnetic radiation of the electron on the Bohr orbit in the idealized hydrogen atom. An analogous problem for gravitational forces is presented.