We present a system for the visualization of information modeled in terms of a graph on a smartphone. First, we show the adopted visualization paradigm, that allows the user to navigate the graph using a focus-based approach. Second, we tackle the algorithmic challenges posed by the new visualization paradigm, introducing and experimenting effective heuristics. Finally, we show several customizations of the system aimed at exploring and at visualizing popular Web contents like social networks and Wikipedia. Current implementations include the iPhone and the Google Android platforms.