Nowadays there are lots of different app in the market, especially social media, such as, Wechat, Tencent QQ, Facebook, Twitter and so on. However, some of the app exploiting user’s data and which is not a good thing for the user. No one will like their personal information revealed. Some of the app putting lots of advertisements on the user’s front page which users are not interested it. Some of the app giving the data from user to the government. While, for the people who are not criminal they will just feel unhappy with that. Based on these ideas, I decided to make an app called Cy@, it has highly privacy policy protection and based on their behavior to put advertisement. Our objective of the Cy@ will be reach a safety platform for the user and they do not need to worry about their personal information reveal. In addition, we want to make it becomes a very popular app and even getting global.