1. A method for estimating the probability of interaction (PTI) between two avatars sharing the same online virtual environment; each said avatar being associated with a different member of an online social network, said method comprising: determining the time history of virtual world interactions between said members and computing at least one virtual world PTI predictor value; determining the degree of social connection similarity between said members and generating a social connection PTI predictor value; determining the overall PTI using an aggregate function of said at least one virtual world PTI predictor value and said social connection PTI predictor value; and using said overall PTI to control said online virtual environment.