With the rapid development of the Internet，cyberspace has become an important domain of everyday social interactions for teenagers. Cyber interactions have not only helped maintain the established social relations of teenagers，but have expanded their social relations network. The overarching principle for teenagers’ cyber interactions is the pursuit of interactivity itself. To a large extent，internet has changed the patterns of teenagers’ social interactions. For many of them，cyberspace is not merely a media for interaction，but also one for self-presentation. Cyber interactions enable teenagers to present themselves in a more open，multifarious and flexible way. By way of cyber interactions，teenagers build a real interpersonal relationship of mutual confidence. This relationship exists among acquaintances and strangers as well. The cyber interactions of teenagers mainly involve personal interests，feelings and emotional expressions. They can be viewed as a process of sharing personal interests，feelings and emotions among strangers.