—In this paper, we present a collaborative social networking environment, referred to as Quality Social Network (QSN), which enhances the social tagging paradigm by using it as a basis to evaluate the quality of Web resources, on the basis of the user preferences specified by each QSN member. Such features give end users the ability of being aware of the “quality” of the resources they are accessing, based on the opinions of the members of their community, and of being informed whether such resources can be safely used, according to the requirements specified by end users themselves. Besides illustrating the main characteristics of the QSN and its architecture, we describe its prototype implementation, carried out in the framework of the QUATRO Plus EU project, and its application to a use case scenario, involving groups of teenagers from three different European countries, acting as Youth Panels of the Safer Internet EU Programme.