The emergence of the Internet, the social giants of the Internet, has subverted the interaction of information. E-mail is the earliest communication tool after the birth of the Internet, and it still plays a more important role in social life today. Instant messaging (IM, Instant Message) is a younger technology that breaks the boundaries of space and can theoretically connect two people at any location at any time. In 1996, based on the principle of instant messaging, three Israelis developed ICQ and became the pioneer in the field of IM software, while its imitator QQ, after better product design and more correct decisions, has already become a social network in China. Software overlord, and has long been in a monopoly position. But at the beginning of QQ, there was actually another way - QQ chat room, but due to Fax List various factors, it finally fell on the connection of acquaintances. Facebook is a very great product of this era, and its success is the success of using technology to transplant Western social relations into the Internet. It can also be seen here that truly great products often solve a most essential problem in the simplest form (product level). In China, SNS players on the school network, one year and ten months later than Facebook, set off a heat wave for several years, but finally fell silent. There are many reasons, the most important one being the product form that is more suitable for the differential pattern. WeChat is the APP with the highest coverage in China today. There is a view that WeChat is not a social product, but an instant messaging software. The author disagrees. Instant messaging is just a means, and it belongs to the same dimension as writing letters, making phone calls, and sending text messages in history. The greatest value of WeChat is to maintain people's old relationships with the help of mobile real-time communication.