(Albert & Albert, 2004; Liben-Nowell & Kleinberg, 2007; Yan et al., 2007a; Guimera & Sales-Pardo, 2009; Lu et al., 2009; Zhou et al., 2009; Chen et al., 2012a; Eronen & Toivonen, 2012; Hu et al., 2012; Musmeci et al., in press; Yan & Gregory, 2012; Liu et al.,...