Background. In the period of adolescence, friendship plays the key role for developing the adolescent personality, for determining their psychological well-being now and for further living. There is lack of data about the actual size of their online friend zone, adolescent perception of real and virtual friendship, and factual features of their relationships with different categories of users, primarily with virtual friends, who adolescents communicate only in the Internet.

Objective. The quantitative research of the online circle of contacts of Russian adolescnts in social media, their perceptions of real and virtual friendship, and regular features of their communication with real friends and acquaintances, and virtual friends.

Design. The survey among adolescents from Moscow, Russia, and Moscow region, Russia, was conducted (N=366, aged 13-16 years old) using the questionnaire of 43 questions about their friend list size and number of online followers; youths’ relationship with real friends and acquaintances, and virtual friends; the method of the unfinished sentences with the following content analysis aimed to investigate adolescent perception of real and virtual friendship. For comparison, we also used data of the All-Russian survey Kids Online II (N=604) conducted by the Foundation for Internet Development (2010).

Results. The results show that 50% of adolescent contacts (aged 15–16) and 43% aged 13–14 outweighs the lower limit of the Dunbar number (100 social connections). Thus, they are almost equivalent to the quantity of social contact of an adult. Friend zone extension occurs due to real friends and acquaintances, and ‘unknown’ virtual friends (whom the adolescent has not seen in real life), hence raising the issue of such relationships’ quality. The results of the content analysis of adolescent answers about differences between real and virtual friendship show that real friendship is more important to them as it contains Direct interpersonal contact (tactile and visual), Emotional exchange, Trust, Co-Activities, Mutual support. Virtual friendship has been characterized through absence, significant lack and/or negative inversion (e.g. from Trust to Mistrust) of these components. Simultaneously, each second youth has virtual friend, whom he/she trusts enough to share private topics, so that such virtual friends play the role of ‘by chance companions’. Adolescents discuss with them life problems and conflicts with parents (35%), real friends and teachers (51–53%), and also their beloved ones (47%).

Conclusion. The number of online social connections among adolescents exceeds the lower limit of the Dunbar range, comparing with similar indicators in adults. Expansion of the virtual circle of communication occurs both at the expense of real friends and acquaintances, and virtual friends unfamiliar to the child in everyday life, which puts the question of the quality of these relations. Virtual friends act in the role of "casual fellow travelers", because with their help adolescents satisfy the needs for intimate contact. This happens even though the children themselves are aware of the disadvantages of online communication compared to offline relationships. The phenomenon of a virtual friend, therefore, occupies one of the key places in the system of interpersonal relations of a modern adolescent and requires further study. On the whole, the phenomena of the ‘unknown friend’ holds one of the key places in the adolescnet system of relationships, thus requiring special research.