Argumentative activity has been found beneficial for construction of knowledge and evaluation of information in some conditions. Many theorists in CSCL and some empiricists have suggested that graphical representations may help in this endeavor. In the present study, we examine effects of type of ontology and of synchronicity in students that engage intuitively, without training, in e-discussions. Fifty-four Grade 7 students from two classes participated in the study. We tested the effects of using an informal argumentative ontology and control over turn taking on the average number of claims and arguments relevant to the issue at stake, the average number of different types of references to peers (productive, etc.), and on the number of chat expressions (nicknames, swear words, etc.). We found that when providing both an informal argumentative ontology and control over turn taking, students express less chat expressions and fewer references that are not new relevant claims or arguments to their peers, but express more relevant claims and arguments. These findings suggest the immediate beneficial role of the combination of an informal ontology and control over turn taking in the co-elaboration of knowledge.