Internet Studies is an interdisciplinary and multidisciplinary field of fundamental and applied research that integrate different research disciplines with a common object, that is the Internet. This review article gives a definition and a brief description of the structure of Internet Studies as part of the social sciences and introduces research agenda of this field, including most cutting edge research issues. The agenda of Internet Studies related to classical sociological issues are analyzed in more detail: inequality, online communities and social capital as well as topics related to the study of transformations in different spheres of society - politics, public health and medicine, education. Two main theoretical approaches are briefly described, within which the influence of the Internet on society is interpreted: the network society theory and critical theory of the Internet and society. We conclude that the present directions of Internet research have many intersections with each other, and the perspective of a more complete study of the mechanisms, that mediate social changes related to the Internet and connect online and offline sociality into a single space, opens at these intersections.