This brief research commentary on Westland's (2010) article in this issue of Electronic Commerce Research and Applications is intended to add two cautionary notes. He attempts to answer two questions: What is critical mass? And how one can manage a network's growth to reach that mass? He proposes a model for social networks, and shows how the model might possibly be managed. What needs to be remembered is that models are always imperfect. And even when they do describe well the natural behavior of some system, they may not fit as well, once some external influence begins affecting that system. Hence Westland's contribution should be regarded as a definite step forward, but not necessarily the definitive answer to either of the questions it attempts to solve.
Andrew M. Odlyzko