Recently, we observed many networked market are served almost by a single platform, and can called that situation be winner-take-all. We could observed that the top website occupy huge market, and still be the top for long time. Conversely, the other website only shares the tiny market. This paper chooses the biggest Taiwan portal Yahoo!Kimo to be the research case. In addition, the case object is its e-commerce department, which is the Yahoo! only e-commerce department worldwide. Through this case, we could find out the truth of winner-take-all. In this research, we use in-depth interview and combine with secondary data. According to past researches and the situation of Yahoo!Kimo, we address the research question as follow: (1) How does Yahoo!Kimo develop their e-store platforms to maintain their e-commerce leading position in Taiwan. (2) Is there a winner-take-all phenomenon on Yahoo!Kimo? After generalize the data, we found that although Yahoo! first time enters Taiwan not successful. Their strategy is merge different kinds website, such as the leading portal Kimo, the most visiting blog Wretch, and Monday.Tech. They got their human resource and technology sooner, then become the top one portal in Taiwan provides variety services for users. For foreign website and companies enter a new market will be a good role model. Moreover, we prove Yahoo!Kimo is role model of winner-take-all.