One of the major challenges of current ITS research is scaling up to real world learning scenarios. Another one, strictly interwoven, is to integrate human learning with other human activities, such as constructing theories or performing experiments, as it is the case in e-Science. The paper describes the results of the first phase of an ambitious project: EnCOrE for building and using an Encyclopedia of Organic Chemistry by virtual communities communicating on the Web. The current major result is the computational architecture, but perhaps more interesting is the chain of arguments for each of the architectural choices made and the emerging conceptual model supporting human learning within a socio-constructivist approach, consisting of cycles of deductive, inductive and abductive activities on facts - the shared reality - and concepts - their subjective interpretation submitted to negotiations and finally converging to a consensus - .