Editor´s note

It is always exciting and touching to hear from friends or loved ones with whom we have lost contact for years. Social networking has brought us far more than what we could imagine, from friendship and love, to rich business opportunities and even different careers. It has made communication networking technologies a sharpening tool to extend the social circle for people, and help us actively maintain and strengthen our social connections. Nowadays, social networking has already become an integral part of our daily lives. As reported by ComScore, social networking sites such as Facebook and Twitter have reached 82 percent of the world??s online population, representing 1.2 billion users around the world. Meanwhile, fueled by the pervasive adoption of advanced handheld devices and the ubiquitous connections of WiFi/GSM/LTE networks, the usage of mobile social networking has surged. Furthermore, in a survey covering France, Germany, Italy, Spain, and the United Kingdom, in September 2011, among over 55 million accesses of social networking sites, 24 million were from mobile devices, representing 101 percent growth compared to the number in September 2010.