With the advent of the social web (also known as web 2.0) as a new way of communicating ideas, market researchers are faced with a new social space that requires relevant methods to apprehend its segments, analyse opinions and identify trends. As the social web becomes increasingly prominent, the question of its social structure and, consequently, of its segments, has become of the utmost importance. This presentation addresses three issues with respect to the social web as a research field: What is the interest of this field compared to other fields? How is the social web structured and how can it be segmented? How should opinions be analysed?