I.-INTRODUCTION « Free » « libre » or « open source » software (FLOSS) is software whose source-code, which is the explicit expression of the programming work, remains openly accessible. until recently, it was considered that FLOSS only concerned programmers interested in building and sharing a base of programs developed for their own needs (Lakhani and von Hippel, 2003 ; Lakhani and Wolf, 2005 ; Demazière et al., 2006). Today, open source software is increasingly integrated into many commercial offers (e.g., Novell buying Ximian and SuSe, Sun open-sourcing its operating system, IBM open-sourcing its development tool software eclipse, and even Microsoft, who recently decided to distribute some of its software products under open license (1)). Iansiti and richards (2006) identified, amongst the various FLOSS projects, a « moneydriven cluster » where « IT vendors' motives are economic. In this cluster, significant investments have been made in projects that will serve as complementary assets to drive revenues to vendors' core businesses ». Lakhani and Wolf (2005), analyzing the results of an investigation of 684 software developers involved in 287 FLOSS projects, found that « a majority of [their] respon