Studies in computer-mediated communication (CMC) have shown that it has the potential to provide opportunities for ESL learners to actively participate in communication using the target language, to notice inter-language gaps in their language production, and to negotiate meaning by the use of interactional modifications (IMs). The use of certain types of communication tasks also seems to play an important role in how to increase the quantity and quality of interactions among learners. Such a role is believed to affect the effectiveness of language acquisition. This chapter reports the findings of a study that investigates Internet chatting interactions between 28 college-level Indonesian non-native speakers (NNSs) of English using two different communicative language tasks, a jigsaw task and a decision- making task, which are believed to facilitate language acquisition. The main aim of this chapter is to discuss how the differences in tasks may generate different frequencies and types of IMs, as well as the possibilities of employing the results of the study in a classroom environment.