Social Network Analysis is a widely used approach in psychology, as in social science, economics and other fields. The peculiarity of this perspective is that it focuses not on individuals or other social units, but on the relationship between them. In this paper, our aim is to give a general review of this perspective giving a description of resources and principal topics covered by Social Network Analysis. In the first section, we will concentrate on methodological and formal perspectives of analysis. In the last section, we will introduce some recent studies about Social Network and its relationship with Information Technologies, in particular on the Internet. Lastly, we will show how this approach can be useful to study some aspects of the web.