Fig. 6

Number of symmetric and asymmetric links for the five types of relationships for (a) September and (b) June. Overall, over the course of the academic year, the number of symmetric links decreased and the number of asymmetric links increased for most of the relationship types. In (c) we plot the user statistics for close friends were each data point is a user plot in terms of his/her number of asymmetric (non-reciprocated) links as a function of number of symmetric links. We can see some users only had asymmetric friendships, whereas some users only had symmetric friendships