Do social media generate social capital beyond borders between the real and virtual spaces? If so, how do social media function in forming and maintaining social capital? From the beginning of 2011, a huge number of people have seen political turmoil stimulated by use of social media and felt the inner stirrings of people’s cooperative networks via social media. Thus, some people strongly stressed that social media has a great power to change authoritarian regimes from the global political issues perspective. On the other hand, we recognized how social media worked effectively from the local issues perspective, for example in the case of the massive disaster in Japan. Existing media such as TV and newspapers didn’t work well, the Japanese got and exchanged information through social media and in fact some victims were rescued based on information via social media. Both cases, political changes and massive disasters, show information transaction process has been supported by thin trust, generalized reciprocity and loosely tied people’s network, regardless of geographical borders or real/virtual spaces. And some users opened their opinions about governments’ policies or their discontent with the government through social media and discuss with others online. Through this discussing process, it seems that social media plays an important role in fostering a social network leading to social capital. This study reconsiders characteristics of social capital and its role in improving people’s lives through social media. It also examines how social media affects social capital processes, by giving a few examples of using social media under critical social situations.