Along with the development of semiotic theories by Saussure and Peirce, there emerged another branch of semiotics, social semiotics, in the last few decades. In a way, it is a natural development of general semiotics, and is complementary with it. In contrast to general semiotics, it focuses on parole and the application of the semiotic theories to other fields. In the present article, it shows its features different from the Saussurian and Peircian semiotics,traces its path of development and proposes six characteristics which characterize it as appliable semiotics; social in nature, practical in orientation, resource for meaning-making, cross-discipline, variable and changeable, and multimodal. As appliable semiotics, social semiotics works with the following four aspects; resources for social interactions, liability to change along with the change of contexts, following certain semiotic principles, and performing two major functions; representational and interactional. The result of the application of social semiotics is multimodal discourses, whose areas of research include the following four aspects; discourse and social practice, genre, style and modality. Multimodal discourses are coherent in terms of the following four aspects; rhythm, composition, information-linking and dialogue. Finally, a relative comprehensive theoretical framework of social semiotics as appliable semiotics is designed and presented.