In today's global business ecosystem, enabled by advanced technologies in personalization and customization, an individual or business team has more leverage than ever before regarding the choice of communication media and communication tool. Moreover, an individual's personal attributes and preferences should be taken into consideration. As one of the new communication technologies, micro-blogging via the smartphone or other similar mobile devices may be acquired and used by a business person according to the person's preferences. To understand how people use micro-blogging in their decision-making with a smartphone, and how individual attributes such as personality and cultural background impact communication, a study is undertaken with a group of over 300 graduate students from both Korea and the United States. This 2 (Myers-Briggs Type Indicator [MBTI] personality group: diverse vs. similar) X 3 (communication mode: micro-blogging vs. asynchronous vs. face-to-face) X 2 (cultural background: Western culture vs. Eastern culture) factorial designed experiment is expected to reveal the degree of impact of the MBTI personality factor, communication mode, and cultural background on four-person group decision-making. A questionnaire is used as a measurement tool to assess the participants' experience from each group.