Smart phones and environmental sensors make it possible to dynamically monitor the positions and patterns of movements of people in urban areas and public spaces, identify or predict possible dangerous situations (e.g., overcrowded areas) or simply recognize the profitability of a different patterns of distribution and collective movements. In this article, we focus on the problem of using such technologies also to steer the movement of people in public and urban spaces, i.e., suggesting people where to move to eventually reach some desirable global configuration in terms of crowd distribution. In particular, we overview and motivate the general problem of crowd steering, identify the technologies that can be put into play, and the possible strategies to direct people movements. Following, we present the results of a set of simulations that we have performed to assess the effectiveness of two exemplary crowd steering strategies.