Using Vygotsky's notion of double stimulation as an analytical tool, we discuss the complex relationship between tasks, tools, and agency in CSCL environments. Empirically we examine how learners in a Norwegian senior high school class learning English as a foreign language approach and respond to an open-ended and collectively oriented task using a wiki. Our findings show that collectively oriented knowledge and language production takes place locally in small groups as well as in the larger collective of the class, and that learners find it difficult to maintain awareness of both levels of activity. However, when facing a breakdown in the wiki application, learners sustained strategies that carried many of the characteristics of collective production. We argue that there is a need to further theorize the task-tool relationship in activities involving collective knowledge production and that we need to align pedagogical as well as technological designs in order to give support for such efforts.