This paper critically examines the degree to which the design of data accessibility and data ownership impact the research activity and the challenges faced by researchers who take these communities as object of analysis. To illustrate these challenges, I take as example web 2.0 language learning communities, the most well-known being Babbel, Busuu and Livemocha, among all possible types of informal, social network based language learning. This study illustrates the tension between on the one hand, the need for a more evidence based understanding of the under-explored field of informal social network based learning, and on the other hand, the obstacles to this scientific exercise. Finally, I discuss how this tension is situated in the current landscape of global research activity that calls for more open, transparent and participatory structures for data sharing and collaborative research.