When I refer to complexity here, I do not mean the traditional computational complexity. I found that it is interesting to analyze social affairs and organization from a perspective of complexity, such as Making the Wage-and-Salary standard and Organization's competitive strength.
In the past 100 years, human beings had achieved many great projects, such as Manhattan Projects, Apollo Program. However, such projects did by at most tens of thousands people. Nowadays, we build the global Internet. The large collaboration could be conduct more easily than before. Useful and interesting collaboration system should be designed to support the larger collaboration. Perhaps new devices could be implemented to support such collaboration. I found an interesting project, duolingo, which try to organize bilingual to translate the web.