We consider the average probability X of being informed on a gossip in a given social network. The network is modeled within the random graph theory of Erd{ő}s and Rényi. In this theory, a network is characterized by two parameters: the size N and the link probability p. Our experimental data suggest three levels of social inclusion of friendship. The critical value p_c, for which half of agents are informed, scales with the system size as N^-\gamma with \gamma \approx 0.68. Computer simulations show that the probability X varies with p as a sigmoidal curve. Influence of the correlations between neighbors is also evaluated: with increasing clustering coefficient C, X decreases.

PACS numbers: 87.23.Ge; 07.05.Tp