It was found that the distribution of users of social networks by the number of contacts, as well as the statistics of telephone conversations by duration, obtained for different cities on the basis of experimental data, obey the same laws, expressed through a differential equation of the first order. This differential equation contains two phenomenological parameters, one of which is interpreted as the fractal dimension of the communication space, and the second is directly expressed through the Dunbar number or its analogue. Essentially, for all cities under investigation the numerical value of the parameter, interpreted as the fractal dimension of the communication space, remains constant with high accuracy. At the same time, the analogue of the Dunbar number, which describes the distribution of users of social online networks by the number of contacts, correlates with the population of the city. The results obtained are discussed from the point of view of the formation of a global communication network - the noosphere, which, due to the development of telecommunication technologies, is already de facto man-machine system. It is shown that the results obtained confirm the conclusion about the existence of objective laws describing the behavior of human-machine systems, made earlier on the basis of general philosophical considerations.