Social networks link people together, among which a lot of factors influences their complexity. To our understanding, so far most visualization interfaces for social networks have not reflected any of their factors. Therefore, this paper tries to solve such a problem by rectangular cartograms, which is a kind of geographical visualization interface using rectnaguls to represent regions in a map. Besides the relative position of each rectangle can reflect the actual geographical related positions, one of the main feastures of rectangular cartograms is that the area size or the shape of each rectangle can reflect the information of its corresponding region, e.g., the population in that region. This paper proposes a layout approaph for rectangular cartograms with area labeling for social networks, in which each region has a minimum-width constraint for accommodating a text label. As a result, this paper applies a genetic algorithm to finding the area-labeling rectangular cartogram with minimum width under some constraints to meet the practical use in social networks. By doing so, we can visualize the labeling text on each rectangle and observe the information represented by its area size or shape at the same time. Furthermore, the proposed approach is applied to visualizing the distribution of the Facebook popularity of an enterprise in Taiwan. From the cartogram, the text label on each region can be read directly and the relation among regions as well as the popularity can be visualized, so that the enterprise can improve the regisons with poor popularity by the help from the regions with high popularity.